Dealers must include a buyer's guide with the purchase of a used vehicle. This guide gives the condition of the vehicle and states whether it has a warranty or is sold as is.. If you do not receive a buyer's guide with your purchase, you may, depending on the laws in your state, be able to return the car for a refund.his guide gives the condition of the vehicle and states whether it has a warranty or is sold as is.. If you do not receive a buyer's guide with your purchase, you may, depending on the laws in your state, be able to return the car for a refund.