So imagine this scenario: You're out to dinner with your significant other, and it's a special night. You order a bottle of wine, you both choose steaks, get excellent service, and you leave your waiter a big tip. Perfect night, right? Except, you choose to pay with your debit card, and you didn't have enough in your account. And instead of being told your card was denied, your bank covered the transaction and charged you an overdraft penalty.

Ok...so maybe facing a $30 overdraft fee isn't the scariest circumstance, but according to the St. Louis Post Dispatch, U.S. banking customers paid more than 17.5 billion in overdraft fees last year.

Furthermore, AG Nixon warns that if you shop online, you should avoid using ATM cards. If you need to dispute a charge, you are only protected under federal law if you use a credit card. That protection doesn't apply to any other form of payment - check, money order, wire transfer, debit card, Paypal, etc.