Complete and mail the Notice of Sale form. (attached to the bottom of the title) to the.Understand car loans, including what to do before applying, interest rates and APR, and what you can negotiate. 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. I'm new to car financing. What got me confused is that my bank wants purchase agreement or bill of sale before sending out a check to the dealer. An Illinois motor vehicle bill of sale documents the purchase and sale of a motor vehicle between a private seller and buyer in the State of Illinois. A vehicle bill of sale in Illinois is used to document the purchase and sale of a car between a private seller and a buyer. Vehicle Payment Plan Agreement. A vehicle payment plan agreement is a contract between a buyer and seller of a vehicle that agrees to installment payments.