Illinois sellers and buyers require a written contract when selling or buying real estate in this state. However, they can't just draw up any agreement.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. ACCEPTANCE DATE: ("Acceptance Date"). SELLER'S INFORMATION: Seller's Signature: Seller's Name (print):. BUYER agrees to purchase and SELLER agrees to sell the real property, and the improvements thereon, commonly known as: , in the County of. Snag our free home offer letter templates, learn what to include and avoid in your letter, and get the inside scoop on how to deliver it to sellers. A real estate letter of intent (LOI) is a non-binding agreement that outlines the terms of a sale or lease contract. A notice to vacate letter (aka lease termination letter) is a formal letter a tenant writes to their landlord or property manager to end their lease agreement.