Paying for goods and services with a credit card may now cost customers an additional fee. Through a settlement reached from an antitrust suit brought on by a group of retailers, merchants are now allowed to add a service charge equal to their cost for processing a credit card transaction—usually between 1.5 and 3 percent. The rule change—which took effect Jan. 27—affects only credit cards and dictates the surcharge may not exceed 4 percent.

But credit card surcharges are illegal in certain states, and therefore will not affect customers making purchases in California, Connecticut, Florida, Kansas, Maine, Massachusetts, New York, Oklahoma and Texas. Merchants in other states planning on implementing a surcharge for credit card transactions must warn customers in advance. They are required to post a sign in their storefronts announcing the fee and must also disclose it at the checkout counter and again on the customer’s receipt.

Furthermore, a chain of stores must address the surcharge the same in all of its locations. Therefore, if a chain has a store in a state where surcharges are illegal, then it cannot add the additional fee at any of its locations. The rule also dictates that the surcharge must be the same for all types of credit cards a merchant accepts—not jut Visa and Mastercard. Therefore, if a merchant accepts American Express—where surcharge fees are banned—it would not be able to add a surcharge to Visa and Mastercard customers only.

“The bottom line is that very few retailers would be able to surcharge under the settlement, and that the vast majority don’t want to surcharge even if they could,” Craig Sherman, spokesman for the National Retail Federation, said in a statement. “We have discussed the settlement with many, many merchants, and not a single merchant we have spoken to plans to surcharge.”

In fact, Wal-Mart, Sears and Home Depot have all announced they do no plan to add a credit card surcharge.

“In the brick-and-mortar world, no one who does any sort of volume of business is going to want to surcharge because it will drive their customers crazy and slow down transactions,” Ed Mieerzwinski, U.S. PIRG director of programs said.

The ability to surcharge is part of a $7.25 billion deal between Visa, Mastercard, nine major banks and a group of retailers that alleged credit card processing fees were fixed and did not encourage a competitive market. Through the settlement, card issuers said they would reduce merchants’ “swipe fees,” but only for eight months.

More than a dozen retailers and the National Retail Federation asked a judge to reject the settlement in November, claiming “raising consumer prices by adding an ‘interchange tax’ is no remedy for Visa’s and MasterCard’s continuing monopoly abuse. Wal-Mart has said the surcharge will cost consumers “tens of billions of dollars each year,” and Target called the agreement “bad for both retailers and consumers.”

Some merchants, such as Target, have already expressed no interest in passing interchange fees on to customers, and even MasterCard said it doesn’t expect most merchants to put the allowed surcharge into effect.

“The bottom line is that very few retailers would be able to surcharge under the settlement, and that the vast majority don’t want to surcharge even if they could,” Sherman said.