If you're buying the car, you will be expected to sign a document called the Retail Installment Sales Contract (RISC). In this post, we'll explore everything you need to know about car purchase contracts, cancellation agreements, and your rights as a buyer.You'll need to sign the car purchase agreement (or dealer bill of sale), the title, an odometer statement, and sometimes a damage disclosure statement. Please provide DMV with a copy of the purchase agreement showing the amount of sales or use tax you paid to another state. Start the new car buying process and find a Costco Auto Program Approved Dealer near you. Select your new vehicle and enter your membership info to begin. Riverside Chevrolet offers new and used vehicles, as well as service, parts and accessories in FAIRBURY. If you're leasing a vehicle, most finance companies will include a buyout option as part of your lease agreement.