We're doing what you've done a million times, buying a cookie at the corner store. Here's the one we just bought, you can see the receipt. It cost a $1.31 including tax.

Now we're buying another cookie at the same place, exactly the same kind. This one cost $2.31. Why? This one we paid for in cash. This one with a credit card.

This place charges $1 to make a credit card purchase.

But you know what? They can't do that.

Hank Phillippi Ryan, 7News Investigative Reporter”They're being punished for paying with plastic, and that shouldn't be.”

Jon Hurst, Retailers Association of Massachusetts”Well, that shouldn't be.”

But our investigation found even though its against the rules in gas stations, pizza joints, convenience markets, dry cleaners, bakeries and liquor stores, merchants are making customers pay more for using plastic.

Rachael, a customer”I had no idea.”

Rachel's sandwiches cost more than she expected at the restaurant.

Rachael, a customer”All those little fees add up!”

And it's not just fees that are prohibited. Minimum purchases? They can't do that, either. But we found this sign, and this one and this one across the state, they do.

Chris, a customer”I was shocked and upset.”

Chris went in for two chocolate bars then saw this sign. She wound up buying two jars of jelly, two boxes of cookies and several more candy bars just so she could make the minimum and use her card.

Chris, a customer”I thought I would spend about $3 or $4, and actually wound up spending about $25.”

Charging fees and minimums is not illegal, but merchants who do it are breaking their contracts with credit card companies.

“It's a violation to impose any surcharge, maximum or minimum,” Visa says.

MasterCard calls those, “prohibited practices.”

So, why do stores do it anyway?

Merchants insist it's not to rip you off, it's because every time you use a card they have to pay a fee to the credit card company. Sometimes more than 4 percent of the purchase.

This gas station owner, who does not charge extras, showed me statements of fees he pays. For instance, when a customer spends $103 dollars, Tom only gets $99.

Hank Phillippi Ryan, 7News Investigative Reporter”What did you think about that?”

Tom, gas station owner”It was horrible. Why should they get all that money when we're doing all the work?”

Retailers calculate fees total 30 billion dollars a year, and it's killing them.

Jon Hurst, Retailers Association of Massachusetts”Economically it's getting down to whether those stores can stay in business.”

When we visited stores with minimums and fees, all insisted their only alternatives are to refuse to take credit cards or to raise prices for everyone.

So, what are your options? Well, you could pay cash, or like Debby when she saw this $10 minimum sign, walk out.

Debby, a customer”The next time it happens, I'm going to say something.”

In fact, many store managers admitted customers who say “you can't do that” will get the fees waived. But if you don't know the rules, paying with plastic will certainly boost your bill.

Most credit card companies do have hotlines where customers can report stores that charge fees or minimums.

If you find a store charging for using a credit card or requiring a minimum or maximum purchase, contact Visa, MasterCard or the customer service number on the back of your credit card to report it.

(Copyright 2007 Sunbeam Television. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

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