When I first discovered that the gas station closest to my house charges a 3% surcharge if you want to buy fuel with a credit card, I thought, “Who pays cash for gas anymore?” I haven’t regularly paid cash since I was in college and buying fuel $5 at a time. Then I realized that few customers at this station were there for a full tank of gas. This business makes its money selling single cigarettes and running a (not very) secret sports gambling operation. They don’t care if I drive down the road to Weigel’s.

Until recently, I have assumed that the only other place I regularly encounter with the rinky-dink policy of charging extra to use a credit card was the government – which I just excused as another minor annoyance in the long catalogue of bureaucratic inconveniences.

That is, until I took my car to the dealership for service last week. When making the appointment, I was informed that the service department assesses a 3% convenience fee for paying by credit card. When I arrived at the dealership, the service desk displayed a large and prominent sign encouraging customers to pay with VISA, their “preferred payment method.”

Apparently it’s “preferred,” but only if I also prefer to pay extra for the privilege.

After calling around Knoxville, I found that about half of the local auto dealers charge a fee to use a credit card.

Until last week, I thought businesses that charged their customers a separate credit card processing fee were poorly run, technological Neanderthals, still hand writing customer receipts and using pads of pink phone message forms. Or, you know, selling cigarette singles and parlay cards. But apparently not.

Admittedly, credit card processing fees can be substantial – averaging about 3% for businesses like auto parts and service. And the percentage of auto service departments charging customers additional fees to use a credit card has doubled since 2021, from 20% to 40%.

I understand why a low margin business with mostly cash transactions would be tempted to charge a credit card usage fee – think a small coffee shop. But the gross margins for an OEM service/parts department can run as high as 70%, which is why service departments account for approximately 40-50% of a typical dealer’s profit, despite only representing 15-20% of revenue.

Which means they don’t need my 3% to survive.

I’m fine with people making as much money as the market allows. But when a high-end, big-ticket business with 70% margins is nickel and diming me the same way as the corner gas station peddling loose cigarettes and parlay cards, I wonder which business’s customers are the biggest suckers.

David Moon is president of Moon Capital Management. A version of this piece originally appeared in the USA TODAY NETWORK.