Completely normal request but normally you would not sign the bill of sale until money has been exchanged. Yes, you need a bill of sale.State the terms and odometer reading on the BOS. What should you include in your vehicle bill of sale? Seal vehicle deals securely. Use our free template to create a bill of sale with a promissory note for automobiles. Payment details: Write down the sale price and how you agreed to be paid. In most cases, the buyer will pay a lump sum. The MVA provides a Bill of Sale form. The bill of sale for car is a legal transfer of ownership between the buyer and the seller.