PORTLAND, Ore. - Charging customers extra for using a credit card may not be breaking the law, but it is breaking policies between businesses and the credit card companies.

Using a hidden camera, KATU News visited local businesses to show them charging fees that could get them in trouble.

At Hollywood Market, we went inside in search of a snack. With some M&Ms and Reese's Pieces in hand, we approached the counter and were confronted with a common problem. The cashier pointed to a sign and told us because our purchase was under $15, we must pay extra - another 35 cents just for using a credit card.

It is a common frustration.

"It happens all the time when you are at a convenience store or something and you are just trying to pick up a soda or a bag of chips or something," said Greg Lansing.

"I am thrifty," said Janet Baldwin. "I just try to save a buck, or 50 cents. It all adds up."

The manager of the Hollywood Market told KATU News over the phone that his profit margins are slim and the credit card companies charge him 29 cents per transaction just for using the machine.

Other small business owners say that their credit card processing contracts may also include monthly fees and fees based on a percentage of the sale.

Although stores are not breaking the law by charging a per-transaction surcharge, credit card policies are clear:

• MasterCard provided a statement that reads in part: "A merchant must not directly or indirectly require any MasterCard holder to pay a surcharge. However, MasterCard said merchants are allowed to give a discount for cash payments.
• Visa issued this statement: "Visa's rules require merchants to always honor valid Visa cards, regardless of purchase amount."

KATU News visited several businesses where cashiers charged us extra for small purchases:

• A gas station had a sign posted that set its minimum credit card purchase policy at $3. The manager said without the additional 25 cent charge for small credit card purchases, the store would lose money on some sales.
• At a store in downtown Portland, we bought an orange juice and they squeezed an extra 25 cents out of the deal.
• We were charged extra at a store inside an office building as well. The manager of the store, the KOIN Mart, told KATU News by phone: "We can wipe out Visa or MasterCard period - we are doing a favor for our customers."

Business managers were not willing to go on camera but did say they feel justified in the charges, especially for cigarettes, where the profit margins are especially thin.