Ditto on TN title and tags. In addition, if you've bought from a private party or even out of state where sales tax was not paid at the time of purchase (such as RVWholesalers) you will have to pay the sales tax at that time. The exception to this is something like an open utility trailer - we call ours a "mulch trailer" or even a very small, such as a 5 x 8, enclosed utility trailer, they do not require a license. You absolutely need a Bill of Sale, regardless, in the event you move to another state that does require title and tags. When in doubt, call your local vehicle registration for the actual info.