It likely doesn’t make sense to sign a bill of sale before receiving payment for the vehicle you’re selling. The best time to sell a car would be when you have an interested buyer who you know has the money you’re asking for. The bill of sale is a record of a transfer of ownership, including any payments made for that transfer. If your bill of sale reflects that you should receive a specified payment for your vehicle, you need to make sure the payment is received before signing. This is to ensure you aren’t taken advantage of by finalizing the sale of the car to a new owner before you’ve received your money.