It's a good idea to get a bill of sale if you intend to buy or sell an RV. This formal document serves as proof of ownership change from seller to buyer. A Michigan bill of sale allows for the ownership transfer of personal property, commonly a vehicle, from a seller to a buyer.A recreational vehicle (RV) bill of sale outlines a transaction between a buyer and seller involving the purchase or exchange of an RV. Reassigned title or registration, or a bill of sale from dealer or the owner for snowmobiles purchased out of state. Registrations are valid for three years. The Michigan RV Bill of Sale form is a legal document that records the transfer of ownership of a recreational vehicle from the seller to the buyer within.