Do not tell the car dealer if you intend to pay for the car up front, in full. Automobile dealers make their money from financing your purchase via auto loans and monthly payment plans. If you do not tell the dealer you are going to pay for the car in full, you will be dangling this possibility of more profit in front of them. By contrast, if the dealer knows he or she will not be making additional money from selling you financing options, they will charge you more for the car itself.