I live in AZ. I bought a trailer last year in NV who did not charge my sales tax. They gave me a temporary transport permit so I could to to AZ. I then registered the trailer at AZ DMV and paid the full AZ tax and registration fees.
NV and AZ have tax agreements in place. If buying between two states that do not have such agreements in place you'll pay the tax rate of the state you're purchasing in and then pay the difference in your home state when registering. If the purchase state is at a higher rate you won't be refunded the difference.