If you look around at online dealers, you will notice that they often have different prices listed according to payment method. Dealers will typically offer a discount for cash, check or bank wire payments and may charge more for purchases made with a credit card.
The reason for this is simple: Dealers typically operate on razor-thin margins and credit card companies may charge one to several percent to process the transaction. Dealers are not able to simply absorb this cost and therefore must charge more to cover the cost of the transaction.