Skip to main content
Skip to Filters
60 listings
  • $25,997
    fair price
    $1,270 below market
    85,167 miles
    1 Accident, 2 Owners, Personal use
    6cyl Automatic
    Lexus of Watertown (6 mi away)
    Home delivery*Five Star Dealer
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Watertown, MA / 6 miles away from Boston, MA

    Nav System, Moonroof, Heated Leather Seats, Rear Air, Aluminum Wheels, Turbo Charged Engine, All Wheel Drive. SERVICE WORK This vehicle meets Massac...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF46JA135165
    Stock: 1501580A
    Certified Pre-Owned: No
    Listed since: 03-18-2024

  • $29,795
    fair price
    $709 below market
    58,230 miles
    No accidents, Personal use only
    6cyl Automatic
    Foley Motorsports (32 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Sunroof/Moonroof
    • Keyless Entry/Start
    Close

    Located in Shrewsbury, MA / 32 miles away from Boston, MA

    2018 Audi S4 3.0 TFSI Premium Plus Quattro AWD... Ibis White on Black Fine Nappa Leather Seating w Diamond Stitching... 8.5 X 19 Audi Sport 5-V-Spoke ...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF40JA234659
    Stock: 19256
    Certified Pre-Owned: No

  • $32,495
    fair price
    $485 below market
    37,831 miles
    No accidents, Personal use only
    6cyl Automatic
    Foley Motorsports (32 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Sunroof/Moonroof
    • Keyless Entry/Start
    Close

    Located in Shrewsbury, MA / 32 miles away from Boston, MA

    2018 Audi S4 3.0 TFSI Premium Plus Quattro AWD... Florett Silver on Black Fine Nappa leather Seating w Diamond Stitching... 3.0L TFSI Twin-Scroll Turb...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF44JA018345
    Stock: 19345
    Certified Pre-Owned: No

  • 27,660 miles
    No accidents, 1 Owner, Personal use
    6cyl Automatic
    Audi Brookline, A Herb Chambers Company (4 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Brookline, MA / 4 miles away from Boston, MA

    INSPECTION COMPLETED Every Herb Chambers Certified pre-owned vehicles receives a complete multi-point inspection by factory trained technicians who in...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF42KA110815
    Stock: 411455A
    Certified Pre-Owned: No
    Listed since: 04-16-2024

  • $24,990
    good price
    $1,267 below market
    92,047 miles
    No accidents, 2 Owners, Personal use
    6cyl Automatic
    European Motorcars (98 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Middletown, CT / 98 miles away from Boston, MA

    CERTIFIED CARFAX HISTORY REPORT - FINE NAPPA LEATHER UPHOLSTERY - MASSAGE SEATS W/VIRTUAL COCKPIT - HEATED FRONT AND REAR SEATS - HEATED STEERING WHEE...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF42JA227888
    Stock: 227888
    Certified Pre-Owned: No
    Listed since: 03-16-2024

  • $29,800
    fair price
    $771 below market
    55,172 miles
    No accidents, 2 Owners, Personal use
    6cyl Automatic
    Pinnacle Imports (15 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Stoughton, MA / 15 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF47JA003077
    Stock: 2834
    Certified Pre-Owned: No
    Listed since: 03-28-2024

  • Price Drop
    $28,693
    fair price
    $998 below market
    62,103 miles
    No accidents, 2 Owners, Personal use only
    6cyl Automatic
    Mastria Volkswagen of Raynham (31 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Raynham, MA / 31 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF46JA003958
    Stock: PV4966A
    Certified Pre-Owned: No
    Listed since: 03-12-2024

  • $32,408
    fair price
    $233 below market
    37,039 miles
    No accidents, 3 Owners, Personal use only
    6cyl Automatic
    Dan O'Brien Jeep Chrysler Dodge Ram of Methuen (27 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Methuen, MA / 27 miles away from Boston, MA

    Recent Arrival!

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF41JA018657
    Stock: X194384A
    Certified Pre-Owned: No
    Listed since: 04-24-2024

  • $28,636
    fair price
    $1,201 below market
    64,179 miles
    No accidents, 2 Owners, Rental vehicle
    6cyl Automatic
    Volkswagen of Old Saybrook (99 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Sunroof/Moonroof
    • Keyless Entry/Start
    Close

    Located in Old Saybrook, CT / 99 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: No

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF4XJA001243
    Stock: V24280A
    Certified Pre-Owned: No
    Listed since: 04-26-2024

  • New Listing
    Stock photo**
    $33,593
    fair price
    $1,050 below market
    23,994 miles
    No accidents, 1 Owner, Personal use only
    6cyl Automatic
    Audi Nashua (35 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Sunroof/Moonroof
    • Keyless Entry/Start
    Close

    Located in Nashua, NH / 35 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF49JA003744
    Stock: ER051204A
    Certified Pre-Owned: No
    Listed since: 04-30-2024

  • New Listing
    Stock photo**
    $32,993
    fair price
    $623 below market
    31,392 miles
    No accidents, 1 Owner, Personal use
    6cyl Automatic
    Audi Nashua (35 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Nashua, NH / 35 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF47JA143890
    Stock: EU7968
    Certified Pre-Owned: No
    Listed since: 04-30-2024

  • $26,991
    fair price
    $829 below market
    85,975 miles
    4 Accidents, 1 Owner, Personal use only
    6cyl Automatic
    Choice Auto Center (35 mi away)
    • AWD/4WD
    • Bluetooth
    • Navigation
    • Leather Seats
    • Sunroof/Moonroof
    Close

    Located in Shrewsbury, MA / 35 miles away from Boston, MA

    Shop Choiceautocenter.com WE TAKE TRADES & WE BUY CARS! Please contact us to schedule an appointment. We use market based data to price our inventory ...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUC4AF45JA134173
    Stock: C5216
    Certified Pre-Owned: No
    Listed since: 11-17-2023

  • $27,950
    fair price
    $952 below market
    77,963 miles
    1 Accident, 3 Owners, Corporate fleet vehicle
    6cyl Automatic
    DC Motors (36 mi away)
    • AWD/4WD
    • Bluetooth
    • Navigation
    • Leather Seats
    • Sunroof/Moonroof
    Close

    Located in Hampstead, NH / 36 miles away from Boston, MA

    Visit Milford Auto Annex LLC dba DC Motors online at www.dcmotorsnh.com to see more pictures of this vehicle or call us at 6**-9**-3*** today to sched...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: No

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUC4AF43JA049946
    Stock: 1911A
    Certified Pre-Owned: No
    Listed since: 04-09-2024

  • New Listing
    $23,498
    fair price
    $279 below market
    101,960 miles
    2 Accidents, 3 Owners, Personal use
    6cyl Automatic
    King Richards Auto Center (40 mi away)
    • AWD/4WD
    • Bluetooth
    • Navigation
    • Leather Seats
    • Sunroof/Moonroof
    Close

    Located in East Providence, RI / 40 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUC4AF45JA003809
    Stock: P11678
    Certified Pre-Owned: No
    Listed since: 04-25-2024

  • 35,226 miles
    No accidents, 1 Owner, Personal use only
    6cyl Automatic
    CarMax (In-stock online)
    Delivery available*
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Santa Rosa, CA / 2,691 miles away from Boston, MA

    CarMax values transparency and wants you to love your next car, not settle on it. Certain vehicles may have unrepaired safety recalls. Check nhtsa.gov...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF41JA004368
    Stock: 25732640
    Certified Pre-Owned: No

  • New Listing
    19,518 miles
    6cyl Automatic
    Carvana (In-stock online)
    Free home delivery*
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Sunroof/Moonroof
    Close

    Located in Charlotte, NC / 719 miles away from Boston, MA

    At Carvana, we go miles beyond the extra mile. That's why we provide you with a convenient, fast, and hassle-free car buying experience that puts you ...

    AutoCheck Vehicle History Summary Unavailable.

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF44JA208095
    Stock: 2002859145
    Certified Pre-Owned: No
    Listed since: 04-25-2024

  • Price Drop
    68,890 miles
    1 Accident, 2 Owners, Corporate fleet vehicle
    6cyl Automatic
    WR Cars Inc (19 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Whitman, MA / 19 miles away from Boston, MA

    Ask us about our First Time Buyer's Program!Price Does Not Include Standard $400 Documentation Fee, sales tax, and extended warranty. - - - - - - - - ...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: No

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF41JA002202
    Stock: WR6096
    Certified Pre-Owned: No
    Listed since: 04-03-2024

  • 78,423 miles
    1 Accident, 2 Owners, Personal use
    6cyl Automatic
    AGM Auto Sales (5 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Leather Seats
    • Sunroof/Moonroof
    Close

    Located in Malden, MA / 5 miles away from Boston, MA

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: No

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF45JA024641
    Stock: 1450
    Certified Pre-Owned: No
    Listed since: 01-17-2024

  • New Listing
    Stock photo**
    $33,993
    great price
    $1,789 below market
    34,309 miles
    No accidents, 1 Owner, Personal use
    6cyl Automatic
    Audi Nashua (35 mi away)
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Sunroof/Moonroof
    Close

    Located in Nashua, NH / 35 miles away from Boston, MA

    Recent Arrival!* CLEAN CARFAX, * PREMIUM PLUS PACKAGE, * NAVIGATION, * BACKUP CAMERA, * HEATED SEATS, * BLACK OPTIC PKG, * QUATTRO AWD, * BLUETOOTH, *...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF41KA045973
    Stock: EU7973
    Certified Pre-Owned: No
    Listed since: 05-02-2024

  • New Listing
    $31,990
    good price
    $1,202 below market
    54,402 miles
    No accidents, 2 Owners, Personal use
    6cyl Automatic
    Carvana (In-stock online)
    Free home delivery*
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Navigation
    • Leather Seats
    Close

    Located in Sacramento, CA / 2,625 miles away from Boston, MA

    At Carvana, we go miles beyond the extra mile. That's why we provide you with a convenient, fast, and hassle-free car buying experience that puts you ...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUB4AF42KA000931
    Stock: 2002869584
    Certified Pre-Owned: No
    Listed since: 04-29-2024

  • Price Drop
    $35,590
    fair price
    $76 above market
    28,138 miles
    No accidents, 1 Owner, Personal use
    6cyl Automatic
    Carvana (In-stock online)
    Free home delivery*
    • AWD/4WD
    • Back-up camera
    • Bluetooth
    • Sunroof/Moonroof
    • Keyless Entry/Start
    Close

    Located in Phoenix, AZ / 2,291 miles away from Boston, MA

    At Carvana, we go miles beyond the extra mile. That's why we provide you with a convenient, fast, and hassle-free car buying experience that puts you ...

    AutoCheck Vehicle History Summary

    Accident Free Vehicle: Yes

    Personal Use Only: Yes

    History Provider: AutoCheck

    Title Details: Clean Title

    Salvage Vehicle: No

    Frame Damage: No

    Theft History: No

    Lemon Status: No

    Free History Report: No

    Features and Specs:

    24 Combined MPG (21 City/30 Highway)

    Listing Information:

    VIN: WAUA4AF48KA011217
    Stock: 2002851630
    Certified Pre-Owned: No
    Listed since: 04-26-2024

Showing 1 - 21 out of 60 listings

Consumer Reviews for the Audi S4

Read recent reviews for the Audi S4
Overall Consumer Rating
4.5 out of 5 stars11 Reviews
Write a vehicle reviewSee all 11 reviews
  • 5 star
    (82%)
  • 4 star
    (9%)
  • 3 star
    (0%)
  • 2 star
    (0%)
  • 1 star
    (9%)
5 out of 5 stars

Simply Fantastic! Coast to Coast! 2018 S4 Prestige

Chris, 07/23/2017
2018 Audi S4 Prestige quattro 4dr Sedan AWD (3.0L 6cyl Turbo 8A)
Coming from a 328i and being a BMW fan in general I was very skeptical, with high expectations, for the S4 and I felt like I was taking a risk when I purchased this car. Looking back, I honestly feel I could not have made a better decision. This car is simply amazing in every way. I recently drove this car coast to coast from New Jersey to San Diego and had plenty of time to break it in. … Ride comfort: 40 hours and 2 1/2 days never went so fast... the Quattro handled torrential downpours to aggressive cornering like a dream. Fatigue was not an issue with the 3-way massaging seats! Driving Dynamics: The S4 accelerates like a rocket and handles like a dream at any speed. The different driving modes are critical as road conditions change. I loved how the Dynamic mode handled the winding mountains in the Southwest with ease and the comfort mode was smooth sailing through the various construction work zones across the country. Tech: The high end gizmos in the new Audi's was what finally pushed me away from BMW and towards Audi. The adjustable color heads up display with Navigation and speed sign recognition worked great! Crossing America, I never had to worry about the changes in the speed limit from a high of 75 to a low of 45 in the work zones... The cameras always caught the sign changes. I had never used lane keeping assist before so there was an adjustment period but once I got used to it... it was a blessing. After hours of driving and possible fatigue it felt like you had a guardian angel by your side giving you gentle nudges to keep you on track day or night. Having Navigation on dual screens is quite nice and extremely customizable, especially zoom in/out with the scroll of your thumb. The only negative I have is that the download speeds of the Audi Connect when searching weather or traffic updates was a bit slow but not surprising considering all the digital processing constantly going on with the car. Overall this car is a dream machine that I plan to enjoy for many years to come.
Report abuse

Used 2018 Audi S4 in Boston, MA Values

Estimated values
2018 Audi S4 Premium Plus quattro 4dr Sedan AWD (3.0L 6cyl Turbo 8A) with no options
ConditionTrade-InPrivate PartyDealer Retail
Outstanding$23,755$27,888$31,585
Clean$23,069$27,051$30,602
Average$21,924$25,655$28,963
Rough$20,437$23,842$26,833

The average list price of a used 2018 Audi S4 in Boston, Massachusetts is $30,700. The average mileage on a used Audi S4 2018 for sale in Boston, Massachusetts is 55,220. Based on the average mileage of 55,220 for used 2018 Audi S4 for sale in Boston, MA and using an average vehicle condition rating, which means the vehicle may have a few mechanical and/or cosmetic problems and may require a considerable amount of reconditioning, we appraise the average trade-in value of a used Audi S4 2018 in Boston, Massachusetts to be $21,924.

Select Buying Experience
Filters
Skip to Results

Location

Search radius100 miles
Search radius

Make & Model

make

model

Year

to
Year

Condition

Price & Payment

60 cars
|
$32,592 avg. price
$
to
$
Price

Price Rating

Edmunds' ratings are backed by 15+ years of pricing research done by our data scientistsHow are ratings determined?We analyze millions of data points to generate our ratings. We look at vehicle configuration, options, history, nearby transactions, market pricing and more — the ratings are up-to-date and relevant to your search area.

Type

Trim

Mileage

to
Mileage

Vehicle History

Engine & Drivetrain

Transmission

Engine Type

Drivetrain

Cylinders

Exterior Color

Interior Color

Total Seating

Features

Comfort & Convenience

Safety

Engine & Exterior

Entertainment

Options & Packages

MPG

to
MPG

Vehicle Listing Details


* Delivery of any kind does not apply to Alaska and Hawaii. Contact the dealer for delivery details, restrictions and costs.