Probably the best and fastest way to get the correct info is to call your license branch. If you're buying from a dealer, you'll pay the sales tax at that time. From a private party, you'll pay it when you go to register....either way, ya gotta pay sales tax....and you'll need the Bill of Sale if from a private party. In TN we pay a yearly tag fee, which is really just a little sticker, and it's a whole $14, so I can't complain.
In case your next question is re insurance....ours is with our auto policy and runs about $75 or so per 6 month period. It covers damages and theft + a handful of other things. Your personal property inside the trailer or things like chairs or RV rugs would also be covered under your homeowner policy. We've found that by keeping all our insurance with one company - in our case, Farm Bureau - that you eliminate the back and forth of who is going to pay what. Farm Bureau is going to cover it and we don't care which policy it's under. BTW, while towing, a TT is covered under the auto policy.