A Washington residential purchase agreement is used when making an offer to purchase real estate. The agreement initiates the negotiation process.A purchase and sale agreement is a contract between a buyer and seller for transacting a property in exchange for a specific price. 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. Free Real Estate Purchase Agreement. Answer a few simple questions. How do I fill this out? Use this free customizable owner financing contract template to confirm financing between the owner selling a home and a buyer purchasing it.