Where are you buying it. Come down to Oklahoma to buy, there is no sales tax collected, only an excise collected first time a vehicle is registered here. The dealer collects no taxes on a vehicle. (But a FW is not necessarily a vehicle here, so I don't know how that might be handled at point of sale, whether dealer collects sales tax or state comes after us for use tax later if we choose not to register a trailer as a vehicle).
I've bought out of state in other states, and had to pay sales tax in the state of purchase, and get temporary title and tag in that state, before I could move off the dealer's lot.
So it is very much a "which state" question.