A vehicle purchase agreement represents the document that lists the legal obligations of both the buyer and seller. This is a tutorial on the California residential purchase agreement.When buying a vehicle or equipment for your business, use this Vehicle and Equipment Purchase Agreement to protect yourself from unwarranted liabilities. Below, we've outlined the steps and forms required for how to sell a car in the state of California so you can sell your car quickly for the most cash. California law prohibits a dealership from giving a customer a purchase agreement before the vehicle is on their property. June 2022 Forms Release. The CAR Commercial Property Purchase Agreement is a pivotal document that governs the purchase of commercial real estate in California.