As gas tops $4 a gallon, gas station operators nationwide complain that interchange fees charged by credit card companies take almost 10 cents a gallon. Stations, which typically mark up gasoline by 11 to 12 cents a gallon, are seeing profits shrink or even reverse.

"At these prices, people aren't making any money," said Jeff Lenard, spokesman for the Alexandria, Va.-based National Association of Convenience Stores. "It's brutal."

Some stations are hanging signs on the pumps: "No more credit cards."

The trend apparently has not reached the Black Hills-Badlands area.

Bernice Crew, owner of Badlands Trading Post located off of Interstate 90 at Cactus Flat, said she has heard nothing about stopping customers from paying with credit cards.

"We love our credit card people. Tourists have credit cards, I don't know how else they would travel," Crew said.

Justin Westby, manager of Wall Auto Livery, has heard no talk of banning credit cards at the pumps either. He said if cards were banned, it would put more of a strain on employees inside the store.

"That would just create a lot more customers inside," he said.

Westby said, although it would be nice to get customers inside the store, there is a large number of customers who pay outside at the pump and might not like having to come inside to pay.

Officials at Big D Oil Company, MG Oil Company and Moyle Petroleum, operators of Rapid City-area convenience stores, did not return the Journal's calls seeking comment.

The National Association of Convenience Stores reports about two-thirds of transactions at gas stations were with credit or debit cards in 2007, a figure expected to rise this year.

The way credit card interchange fees are structured has long annoyed retailers, prompting calls for relief.

Legislation pending in the U.S. House and Senate would allow merchants to bargain collectively with major credit and debit card companies.

The National Retail Federation says gas prices point to the unfairness of the system: Gas stations are paying more in interchange fees because the price of gas has gone up, while the cost of processing credit or debit cards remains the same.

"We have always contended that it doesn't cost Visa and MasterCard any more to process a $1,000 transaction than it does a $100 transaction," said J. Craig Shearman, vice president of government affairs at the retail federation.

The credit card companies say fees are just part of the cost of doing business.

MasterCard has capped interchange fees for gas purchases of $50 or more, said company spokeswoman Sharon Gamsin.

Accepting MasterCard also gives gas stations "increased sales, greater security and convenience, lower labor costs and speed for their customers at the pump," Gamsin said in an e-mail to The Associated Press.

Visa argues that the fees are offset "by the tangible benefits to stations and their customers, such as the ability to pay at the pump," the company said in a statement to the AP.

Absent congressional action, gas stations are seeking other relief, including discounts to customers who pay in cash.

Shipley Energy, which owns 23 Tom's Convenience stores in Pennsylvania, has partnered with a new credit card company, Revolution, which charges smaller interchange fees.

Bob Astor, wholesale fuels business manager, said those savings get passed on to customers as cheaper prices at the pump. Customers who pay with the card get an automatic 10-cent discount.

Gas stations in South Carolina, Georgia, Maryland, New Jersey and Arizona are among those offering cash customers a discount, with savings from four cents to 10 cents per gallon.

The Associated Press contributed to this report.