I have now purchased 5 cars with my credit card. Simply stated, a dealership can not deny your use of a credit card to purchase your car.

I go in and simply negotiate the price. I tell them they will have their money before I walk out, if we reach a mutually agreeable price. I do not lie, I do not ever mention check or cash or credit card. I just negotiate.

Once the sales price is set, keep in mind that they want you to sign the papers as quickly as possible. They want your signature on a contract.....which they also must sign! Then, they take you to the finance guy. And that's when they say "We do not take credit cards." I tell them that "You must." And they again say "Nope."

I walk out. Plain and simple. They stare, and can't believe I am walking away.

At home, I have a standard letter which I have used each time and fax to the owner. In summary, I remind them that the legal department of VISA International has advised me in writing (copy of VISA letter attached) of the following conditions in the contract which dealership must have signed with your financial institution:
1) Merchants are not permitted to establish a minimum or maximum transaction amount.
2) Merchants are not permitted to pass on the transaction fee to the cardholder.
Simply stated, if dealership accepts a credit card for any type of purchase (such as in their service dept), then they must accept the credit card for all transactions, regardless of the amount.

I suggest that they contact thier financial institution or their legal counsel to determine what the dealership's rights and obligations are.

I always end the letter with "I would appreciate a reply tomorrow morning, so that I can conlcude our transaction and pick up my new car during lunch."

It's never failed. ^

As added protection, I always call the credit card company ahead of time, giving them notice that I am about to make a large purchase, so they won't decline the charge.