A car purchase agreement serves as a contract between you and the dealer that finalizes the terms of your car purchase. The dealer may call it a car purchase agreement, a car sale agreement or dealer bill of sale. However, a bill of sale is typically a simplified version used when buying a used car from a private party. The car purchase agreement is an official document that outlines all the details of the sale, including: Vehicle make, model, color, and VIN Seller's (dealer's) and buyer's names, addresses, and signatures Itemized purchase price, fees, and taxes Financing details (Learn about car financing documents) Any other information relevant to the sale