To help you purchase your "forever" home, we'll explain exactly what you should include in your offer letter. Do you know how to write an offer letter for a house?We're here to teach you the ins and outs to improve your chance of closing a deal. This fill-in-the-blank form can be used to change or extend inspection, signing, financing or other dates contained in a signed real estate contract. From: ("Buyer") TO: ("Seller"). Purchase and Sale Agreement. A purchase and sale agreement is a contract between a buyer and seller for transacting a property in exchange for a specific price. Searching for Massachusetts purchase and sale agreement? Parties: the "SELLER," agrees to sell and. , the "BUYER," agrees to buy, the premises described in paragraph 2 on the terms set forth below.