It may just be a Missouri thing. Unlike some other states, tax is not paid at the dealer, it is paid within 30 days at the Department of Motor Vehicles. You can not get your tags until you do. When you sell your old vehilcle, you get your bill of sale and show it to the DMV. They subtract the value of your previous vehicle from the price of your new one. Since I sold my 02 for 6200, I'm only paying taxes on 3 grand. Check your state.