Customize and Download this "Bill Of Sale With Payment Plan". 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. Payment : The bill of sale document should also state the method of payment used such as installments or in full, cash, check, credit card or bank deposit. Monthly payment amounts must be received timely on or before predetermined installment dates. The California bill of sale form helps individuals document data on a transaction involving the sale, trade, or gift of personal property. These templates typically include all necessary sections, such as buyer and seller information, trailer specifics, price, and signatures. California Bill of Sale Forms (3). A California bill of sale is an official document used to record the sale of personal property between a buyer and seller.