NEW YORK -- These days, it's easy to rack up hundreds of dollars in interest charges on a single credit card.

NewsChannel 4 has seen offers that tease consumers with low rates-like 2.9 or 3.9 percent -- but those offers never last.

Well, now they can -- but only if you transfer a balance.

"They are such a great deal because they are for the life of the entire balance that you transfer," said Curtis Arnold of CardRatings.com.

Several companies are trying out that tactic, while a few others are experimenting with an even better offer -- zero interest until that transfer is paid.

But there are a few catches that come with these offers.

"There is fine print like any other credit card offer, and particularly on these offers," Arnold said.

One big catch...with at least one of the card companies, you have to keep charging.

"You're going to have to actually make two purchases a month," he said.

Another catch with all of the issuers any payments you make are applied first to the initial transfer.

"The payments that you make on the card are going to actually go to the lower interest rate," he said.

That means you'll be paying off your new charges last -- and don't forget, the interest rate on those is in the teens. And for all your no or low interest transfers, make sure you don't miss a payment.

"If you're late on any of these offers, even one time, your interest rate will jack up to the normal purchase rate," Arnold said.

If you can discipline yourself to make sure your payments are on time and your new purchases are small, this may be a smart way to pay back some hefty debt without paying hefty interest.