3. Find the Incentives for the Vehicles on Your List
It's possible that the salesperson you'll be dealing with won't know about all of the available incentives for a plug-in electric car. So you should.
The federal incentive is fairly easy. It's an income tax credit, not a rebate. If you finance the car, you'll do so on the price before the tax credit. The credit is based on battery size and vehicle range. The Department of Energy's fueleconomy.gov site carries a fairly up-to-date list of which plug-in electric cars qualify for what.
The basic rule of thumb for EV federal tax credits is that all-electric vehicles have large enough batteries to qualify for the maximum benefit, which is a tax credit of up to $7,500. It is applicable only in the year in which you buy and can only be used to offset your federal income taxes. There's no cash refund if your tax bill is less than the incentive.
Federal plug-in vehicle credits range from as little as $3,667 to as much as $7,500. Again, these are maximums, dependent on the size of your federal tax bill.
State and local incentives include reduced electricity rates, free parking, carpool lane use, help buying home chargers, and cash rebates and tax credits for vehicles. But not all states and communities offer incentives. They also change frequently. A good source is Plug In America's easy-to-use interactive state and federal incentives map.
You should also call your city hall to see if you are eligible for local benefits that aren't on the National Council or Plug In America lists. Check with your local electric utility company to see what kinds of help it might be offering. Utility company websites often list special-rate programs for people who own a plug-in car.
Your car salesperson should be able to tell you about any applicable manufacturer incentives. But you also can find them for yourself by checking out Edmunds' incentives and rebates center or by visiting the manufacturer's website for the model you're considering.