Customize and Download this "Bill Of Sale With Payment Plan". Click here for the Application and Agreement for Installment Payment Plan.Riverside County Treasurer PO Box 12005, Riverside, CA 92502-2205 (951) 955-3900 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. This Equipment Purchase Agreement ("Agreement") is entered into this _____ day of. Use the SEARCH BAR above to find your form more quickly. Just type in the name of the form. To apply for a payment plan, complete this application and submit the form with all required supporting documentation. Selling or transferring ownership of a car, boat or other item of personal property?