What paperwork do I need when buying a used car from a private seller?

Typically you need the signed-over title, a bill of sale with price, date, VIN and both parties' signatures, an odometer disclosure where required, and a lien release if the car was financed. Some states also require a smog or safety inspection certificate. You'll need proof of insurance to register it. Requirements vary, so check your state DMV's website before you pay.