Next time you use a debit card to buy a $5 latte, make sure your checking account has enough cash to cover it. Otherwise, that latte could cost you close to $40, thanks to the overdraft fees you'll incur.

In order to get more money out of consumers, banks and credit unions have increased overdraft fees and made it easier to trigger them, says Jean Ann Fox, director of financial services for the Consumer Federation of America. At the heart of the problem are so-called "courtesy" overdraft policies, which allow banks to pay charges that would otherwise bounce. Instead of incurring an insufficient funds fee, account holders get hit with overdraft fees that can run as high as $35.

"It's the only form of credit that can be involuntarily imposed on you," says Chi Chi Wu, staff attorney at the National Consumer Law Center. "There's no point to it except to generate fees." Financial institutions collect more than $17.5 billion in overdraft fees per year, according to the Center for Responsible Lending (CRL), a nonprofit policy group.

There are, however, positive developments on the consumer front. Working its way through Congress is the Consumer Overdraft Protection Fair Practices Act, legislation that aims to prohibit overdraft fees unless the consumer opts for "courtesy" overdrafts. Even if a consumer opts for overdraft protection, they must receive a warning of an impending fee before they finalize a purchase that may trigger the overdraft fee.

Consumers don't have to wait for the legislation to get signed into law to avoid overdraft fees. They just need to be proactive about their accounts and buying habits.