With the economy tanking, credit card companies are hoping consumers will bail them out in more ways than one. Taxpayers have already sent millions of their own dollars to card companies as part of the federal bailout. But now consumers are being asked to pick up the tab for card companies’ tanking balance sheets. To protect themselves from a spike in consumer defaults, card companies are hiking up interest rates and tacking on new fees, even for responsible borrowers.

The good news is that Congress is introducing legislation that would reign in these fees and require credit card companies to have greater transparency in their business practices

Here are the five most commonly practiced credit card abuses to be aware, Good Morning America reports, at least until 2010 when new Federal Reserve rules prohibiting these practices will take effect (“Top 5 Tricks Credit Card Companies Play,” April 20, 2009).

1. Arbitrary Interest-Rate Hikes

Cardholders can zap you with a higher interest rate at any time, even if you have a low-interest rate credit card, since credit card issuers are free to raise their interest rates whenever they want. Card companies can apply the new, higher interest rate to any new charges made on your card, as well as to your existing card balance.

2. Universal Default Rate Increases

A credit card company can hit you with a higher interest rate on your credit card if you’re late on a payment to an unrelated creditor. If your bank finds out that you were late on a payment for your department store card, your bank can choose to raise the interest rate on your bank card, even if you’ve never missed or been late on any of your bank card payments.

3. Lowest Interest Rate Balances First

Card issuers can choose to apply your monthly card payment to your lowest interest rate debt first before applying it to any secondary interest rate debt, if you have more than one interest rate on your credit card. For example, if you take advantage of a card offering a low introductory interest rate on balance transfers, you could see your monthly payment applied to the transferred balance before your payment is applied to the balance with the higher interest rate, which is typically the balance containing any new purchase charges.

4. Payment Due Date Changes

Card companies can arbitrarily change your payment due date with little advance notice, which can often cause you to make a late payment, leading you to incur late fees and sometimes a rate increase on your low introductory rate credit card.

5. Billing Cycle Double Charges

Cardholders can charge you interest on your monthly purchases twice. If you make a purchase but don’t pay off the purchase balance in full in the first month, your card company can charge you interest on the full balance of the purchase for two months. For example, if you put a $200 purchase on your card but only pay off $150 of the charge in the first month, you could be charged interest on the full $200 the first month and be charged interest on the full balance the following month as well, instead of just being charged interest on the remaining $50 balance the second month.

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