LOS ANGELES >> Consumers may be in for a major break on credit card purchases under an agreement reached Monday between the U.S. Department of Justice and the nation’s two biggest card companies.

At issue are the fees that businesses pay credit card companies such as Visa and MasterCard to process the charges. Until now, merchants had been forbidden to tell consumers about the fees — or offer discounts to customers who use cards that charge merchants lower fees.

But on Monday, Visa and MasterCard agreed to new rules that would let merchants charge less to customers who use credit cards that impose smaller fees on shopkeepers.

"We want to put more money in consumers’ pockets, and by eliminating credit card companies’ anticompetitive rules, we will accomplish exactly that," Attorney General Eric Holder said at an afternoon news conference. "The companies put merchants and their customers in a no-win situation."

The agreement came as part of a lawsuit filed Monday against the major credit card companies by the federal government and several state attorneys general alleging anti-competitive practices. MasterCard and Visa settled. The third card company, American Express, refused to sign on to the agreement.

Retailers have complained for years that credit card companies gouge them by adding a charge of as much as 5 percent of each purchase every time a card is used.

Now businesses will be allowed to charge less if customers use cards that have lower fees — a move that the Justice Department’s lawyers say will lead to more competition between card companies and millions of dollars in savings.

Many merchants, long frustrated by the fees, were pleased. Mitchell Goldstone, who owns Irvine, Calif., photography shop and online business Scanmyphoto.com, welcomed the settlement, saying it would free up merchants to nudge consumers toward using less expensive cards.

"I was very excited today and encouraged by the Department of Justice moving forward," said Goldstone, who is also a plaintiff in a private lawsuit against the credit card companies. After employees and rent, Goldstone said, the fees are his biggest expense.

Merchants pay about $35 billion a year in fees to credit card companies, according to the Justice Department. It’s money that restaurant owners, retailers and others say they can ill afford in the difficult economy.

Consumers know well that credit card companies charge interest, but many are not aware of the merchant fees.

The cost of a swipe varies widely, depending on whether the customer is using a card that offers rewards. It might cost a merchant 2 percent of the purchase price if a customer uses a no-frills card. But if the purchase is made with a card that offers airline miles, for example, the merchant might pay as much as 5 percent.

MasterCard and Visa praised the settlement in news releases. Both companies said that they already allowed some of the measures called for in the agreement.

Josh Floum, general counsel for Visa Inc., said that allowing merchants to offer discounts based on the cost of fees is "a reasonable accommodation."

The company already allows businesses to offer discounts to customers who pay cash or use debit cards for transactions in which they enter their PIN numbers to take cash right out of their accounts.

The agreement is expected to take effect as soon as it gains court approval, perhaps in a few months. The lawsuit and settlement were filed in federal court in New York.

American Express said the agreement was unfair and vowed to fight it in court.

"Our attitude is that this is bad law, bad economic policy," American Express spokesman Michael O’Neill said. "We don’t think there is anything in it for consumers."

Far from offering discounts to consumers, O’Neill said, merchants are just as likely to keep the savings on cheaper credit card fees for themselves.

"You never hear the retail associations say, ‘If we save money on this, we’re going to pass it on to consumers,’ " he said. "They’re not willing to make that commitment."

Moreover, he said, American Express is considerably smaller than Visa and MasterCard, and should not be included as an example of a company large enough to impede competition.

Because American Express did not settle, the lawsuit will continue against the credit card company. The Justice Department says American Express accounts for 24 percent of all credit card spending in the nation. Visa cards are used for 43 percent of transactions and MasterCard 27 percent.

Scott Hauge, president of the advocacy group Small Business California, said credit card fees were a huge issue for small-business owners, many of whom must accept credit cards to stay in business. He urged American Express to drop its resistance to the agreement.

"I’ve always thought it was outrageous that the credit cards could dictate to the merchants with those higher costs," Hauge said. "American Express should be ashamed of themselves."