"It used to be - let's say you slip up and you're a day late on a payment. The credit card companies would triple your interest rate and apply it to your entire, existing balance," said Tamara Draut, vice president of policy and programs for the nonprofit advocacy group Demos. "That they can't do anymore."
Also among the new rules laid out in the Credit Card Accountability, Responsibility, and Disclosure Act:
-Card issuers will not be able to raise your interest rate for 12 months unless you are 60 days past due.
-They will be required to apply payments to the balance with highest interest rate first.
-Monthly bills must show how long it would take you to pay off a balance with only minimum payments.
-Statements must arrive at least 21 days before payment is due, up from 14 days, to help avoid late fees.
"Here's the bad news - there's no limit on how much interest they can charge you. so the sky is still the limit," Draut said.
The credit card industry's lobbying arm, the American Bankers Association, opposes interest rate caps and insists the new rules empower customers.
"The consumer's in control. If they get a notice that there's a new fee or an increase, they can just say no," said Nessa Feddis, vice president and senior counsel for the association.
But critics argue the industry is already looking for ways to make more money. One Citibank customer who spoke to CBS News had his interest rate raised to 30 percent. But if he makes minimum payments on time, the rate would be reduced to 9 percent.
"It's hard to see how that's a trick - giving you back money for good behavior," Feddis said.
Credit cards companies can still lower your credit limit any time for any reason and debit cards are untouched by the new reforms.
"Debit card use is up, as people try to be more careful with their finances, but the banks are catching them from the blind side -- they're putting more fees now on the debit cards," said Mike Calhoun, president of the Center for Responsible Lending
Those fees average $35 any time you overdraw your bank account, costing consumers a total of $13 billion a year.
"People need to be responsible, need to pay for the services they get, but they need to pay under fair rules," Calhoun said.
That's exactly why consumer advocates are pushing for an independent consumer watchdog agency to regulate the credit and debit card industries - something that banks, of course, vehemently oppose.