However, buying a used car from a private party can be problematic. The seller should give you a signed title so you can prove you are the new owner. Depending on the laws of your state, you may also need to apply for a temporary registration so you can drive the used car back home and complete the registration.
If your home state requires a smog certification, this is your responsibility. It's smart, however, to ask the seller for proof that the vehicle has recently passed a smog test so you can see if it is likely to pass in your state.
To sum up: Because of potential registration problems, it's always a good idea to buy cars in your home state. However, if you are a bargain shopper or someone looking for a rare car, the entire nation can be your car lot. Just make sure you understand these three important issues — emissions, sales tax and transportation — before you seal the deal.