A vehicle payment plan agreement is a contract between a buyer and seller of a vehicle that agrees to installment payments. Never sign a contract with spaces left blank, mark them out or fill them in as appropriate."Lender credit card agreement" means an agreement entered into or performed in this state prescribing the terms of retail installment transactions. Use our free payment plan agreement form to spell out all the terms and conditions of a loan if you need to establish a payment schedule with someone. How should I write up an agreement to sell a vehicle at weekly payments? Bill of sale contracts are issued to fill out and get a vehicle to. What should you put in my car sale contract with payments?