Most of us have been there, and as a result, if you’re like the typical 20-something, you’ve got about $9,000 in credit card debt to show for it. And if you’re like most of us, you’ve been surprised by a fee or interest rake hike, often for nothing more serious than mailing a payment a day late.

Thanks to a range of “gotcha” tactics, and no legal bounds to how much they can charge in fees or interest, the credit card life line can quickly feel more like a noose. Congress finally seems to be paying attention and is entertaining the idea of cracking down on some of these abuses, but in the meantime, it’s important to know what to look out for.

Here are some of the most common and most expensive traps:

• Late payment penalties: One late payment—typically defined as a payment received after a specified hour on the due date—can trigger a late payment fee and a substantial hike in your interest rate. The average late fee is now $35, and if you have a higher balance, could cost you $39. To add insult to injury, most issuers will raise your interest rate to what they call the “default rate.” The average default rate is now 24.51 percent, and can be as high as 32 percent.
• Any time, for any reason changes: Most issuers will disclose somewhere in the initial solicitation or in your cardmember agreement this little nugget of information: they can change the terms of your account, including the annual percentage rate (APR), at any time, for any reason. So essentially, how much you end up paying is totally at the whim of the issuer—begging the question, what’s the point of a cardmember agreement anyway? One issuer—Citibank—announced in March 2007 that it was ending this type of unilateral change in terms.
• Universal default: This practice, which is an increase in your interest rate as a result of the way you handle other credit accounts, has generated lots of attention, and many issuers claim they have stopped practicing it. But many issuers will still raise your interest rate based on a change in your credit report—which could happen if you miss or are late on a payment with another creditor. In other words, they’re still practicing universal default, but no longer calling it that.
• Retroactive application of interest rates: It’s bad enough that the card issuers can raise your rate whenever they want to. It’s made even worse because the new, higher rate gets applied to your entire existing balance. This is the equivalent of you buying a computer and having the manufacturer contact you a couple months later to say you owe more money because they’ve since raised the price of the model you purchased. It would never happen, but that’s essentially what card companies are doing when they hike up your interest rate, and apply it retroactively to your existing balance.

File all of this egregious behavior under “borrower beware,” but also know that ultimately what borrowers deserve is real consumer protection. Congress, after long providing a bi-partisan shield of protection for lenders, may finally crack down on some of the most egregious abuses in 2008.

The big card companies visit Congress every day—arguing that any limit on their practices would ultimately be bad news for their cardholders. But we’re not buying it. You can help keep the heat on the credit card companies by sharing your story with us, and adding your voice to the call for change.