The buyer's order (also called the purchase agreement or sales contract) is the most important document. It shows the agreed purchase price, trade-in allowance, down payment, and any products or services included in the deal. Compare it carefully with the retail installment sales contract — discrepancies between the two are often evidence of fraud.

The retail installment sales contract (RISC) is the financing agreement. It shows the vehicle price, down payment, amount financed, interest rate (APR), monthly payment, total of payments, and any products added to the financing. The TILA disclosure box is in the upper right corner of most RISCs. Bring all copies you received — dealers sometimes present multiple versions.

Any advertisements you relied on — online listings, dealer website screenshots, newspaper ads, or printed flyers — are critical evidence if the dealer charged more than the advertised price or misrepresented the vehicle's features. If you can, preserve the original URL and take a screenshot with the date visible.

All written communications with the dealer: emails, text messages, and any written representations about the vehicle's condition, history, or financing. If the dealer made oral representations that are not in writing, write them down as accurately as you can remember, with the date, the name of the person who made them, and the exact words used.

A vehicle history report (Carfax or AutoCheck) if you obtained one before or after the purchase. If the dealer provided a vehicle history report, bring that copy. If you obtained your own report after the sale and it shows damage not disclosed by the dealer, that is important evidence. Also bring any inspection reports, repair orders, or mechanic's assessments of the vehicle's condition.