A Michigan residential purchase agreement is a contract outlining all the terms and conditions of a residential property sale between the buyer and the seller. Here are the 7 best For Sale By Owner websites in Michigan: 1.The paperwork takes about 20 minutes to fill out. For Sale By Owner real estate transactions are increasingly popular in Washtenaw County. Find out how FSBO works for both sellers and buyers. You'll need to fill out or obtain at least 14 documents, including the purchase agreement, closing statement, and bill of sale.