Buyers who purchase cars sold by private sellers are still responsible for paying state sales tax and DMV fees, according to DMV.org. Privately-sold cars usually come with a lower asking price and fewer fees, but the buyer is ultimately responsible for ensuring that the pertinent paperwork is in order.
Used car sales tax rates vary by state, states DMV.org. Dealerships calculate the tax for buyers, but buyers in a private-party transaction must figure out the tax rate on their own. In addition, the buyer must file title transfer and registration paperwork. As with tax, the procedures vary by state. Prospective buyers can contact their DMV for state-specific information.