Sales tax exemption for active duty military

If this is the policy in Tennessee all you should have to do is show the dealer your proof of service but it would not hurt to go to the TN DMV website and print out the exemption to show them.

If I buy a car in another state, would I have to pay state sales tax there, or can I show proof of military assignment in TN to get the exemption?

When buying a vehicle out of your home State you do not pay sales tax at the time of purchase. You pay sales tax to your home State when you do the title transfer and register the vehicle. If you are tax exempt then you will not pay sales tax in your home State of Tennessee when you title and register the vehicle there. Hope that helps! Jim

Dealers should collect the sales tax for your home state.