Before you make payments for your next vehicle with an auto auction website, request for the company's terms and conditions and make sure that you absolutely agree with them. The methods of payments are settled by each company individually and may vary from website to website.
Some car auction companies prefer to receive a bank wire transfer only, however, others may also accept credit card payments for placing a deposit or a full invoice amount. But it's more secure to arrange your transfers via banks, as reliable financial institutions are usually giving you a proof of your payments, and namely a confirmation or payment order.
As for credit cards such as Visa or MasterCard there are some limitations for transferring amount, so you probably will not be able to pay for a car purchase in full via VISA. But it's a more convenient method of payment for placing a minimum deposit. Besides, the average transferring time for bank wire payments is 5-7 business days, while credit or debit card transactions are processed from an hour to two days only. As far as used vehicles are sold very fast on the North American auto auctions, it may be good for you if a car auction website offers its clients to settle a deposit using their debit or credit cards.