New Trailer and Off-Highway Vehicle (OHV) Report of Sale. 1. Gather required information about the seller, buyer, and trailer.You need a California Trailer Bill of Sale form to register your trailer with the DMV after purchasing it from a private party. The California bill of sale form, REG 135, allows a buyer to purchase a motorized vehicle or vessel in the State. All fields should be filled-in on the form. A California motor vehicle bill of sale is part of the vehicle registration process. Use a free template to write your own bill of sale. Dispose of a vehicle or vessel. Checks or money orders for business license and employee permit fees should be made payable to Sacramento County.