Finding a credit card that delivers on promises of a low interest rate can be next to impossible. Even when consumers read all the fine print, they find the terms are subject to change, seemingly at the whim of the credit card company.

For example, John, of New Falmouth, Massachusetts, said he answered an ad for Household Bank's Platinum Mastercard, which offered a 0 percent introductory fixed rate for the first 12 months for purchases and balance transfers.

John's existing credit card charged just over 9 percent, not a bad rate these days. But being a thrifty consumer, John said he wanted to take advantage of the offer of 12 months without interest. So he applied for a card.

"The introductory letter stated that, upon approval, they would send balance transfer checks in my Welcome Kit, to make it easy to transfer balances," John told "I was told that when you use these checks, there is no transaction fee."

Within a week, John said he received a package of material from Household Bank, thanking him for his business. The package contained several checks.

Since it was the only communication he received from Household Bank, John assumed the checks were the balance transfer checks he had requested.

"I then proceeded to make out two balance transfers and sent them off. The next correspondence I received from the bank was a bill showing the transfers ... not at 0%, but at 29.51%! I immediately called customer service."

John said he was told that he most likely had used the wrong checks to transfer his other credit card balances.

It seems that Household Bank has "balance transfer checks" and "credit card checks." The difference?

One supposedly has no transaction fee and allows you to move a high interest balance to the new account at 0 percent interest. Using the other is the same as taking a cash advance on your credit card, the most expensive credit card purchase there is.

John said he was told he had used the wrong check, even though he insists it was the only type of check contained in the bank's "welcome kit."

So now John's previous credit card balances, which were at 9.9 percent with his previous credit card company, have suddenly jumped to nearly 30 percent with Household Bank. And it gets worse.

"Because of the high interest rate, combined with the second balance transfer check I sent, my request was not honored by Household Bank because it would have put me over my credit limit," John said.

That check, John says, ended up bouncing, causing late fees and raising the interest rate on his lower-rate credit card. Sometimes, even reading the fine print doesn't seem to help.