In a business sale, a letter of intent (LOI) is a buyeroriginated document through which the buyer expresses its intent to buy the subject business. Identify the parties involved in the transaction. 2.A purchase agreement is a type of contract that outlines terms and conditions related to the sale of goods. A business purchase agreement marks the official start to the sale of a business. Read our blog to better understand each part of this important document. The nature of financing. We've included a lengthy, typical NYC real estate purchase contract geared towards new development for your review below.