Clearly print or type all information, except signatures. The proof of sale for a vehicle from a dealer is the Retail Certificate of Sale (MV-50) ("Dealer's Bill of Sale").A New York Trailer Bill of Sale helps streamline the registration process and proves the transfer of ownership if a dispute arises. Use this free form for private transactions. It comes in a printable PDF format, and you can quickly fill it out using your completer. There are no titles on sleds in New York. The Trailer is to be sold free and clear of any liens, encumbrances, or mortgages.