Car registration fees are not sales taxes. You only pay the sales tax once, on the purchase. You might pay a use tax if you ship or otherwise transfer the car to another state, but for the most part use tax laws are not well enforced. Sales taxes in most states go into the general fund.
The registration fee is a fixed amount that is not dependent on the price of the car. You pay an annual registration fee in every state in which you reside and intend to use the car. The registration fee in most states goes into a restricted use fund that pays for things like road maintenance.
Similar to what the others say, in GA the ad valorem is paid annually and is based on the value of the vehicle. This is (was?) true in NC circa 2010 (when I moved) as well. Though, now in GA you pay the tax once on new (? not sure the criteria, either vehicle model year or sale date) vehicles, and the sales tax (if purchased in GA) counts as the one time ad valorem.
The registration fee is a fixed amount that is not dependent on the price of the car. You pay an annual registration fee in every state in which you reside and intend to use the car. The registration fee in most states goes into a restricted use fund that pays for things like road maintenance.