A Pennsylvania residential purchase agreement establishes a legal arrangement between a buyer and a seller in a real estate transaction. All of Seller's right, title, and interest in and to the Property on the terms and conditions set forth in this Contract. 3. Terms.I'm gonna break down all the terms and conditions so you can understand what it means and we're gonna fill that out so you can have a real-life example of it. A memorandum of purchase and sale agreement is a legal document that protects a buyer from being outbid after the seller accepts their offer. This is a Legally Binding Contract; If Not Understood, Seek Competent Legal Advice.