Smartphones try to connect to the Internet using Wi-Fi; it's often free so you don't incur connection charges. But if the device doesn't pick up Wi-Fi, it will use a cellular network. And what runs up the bill is usually data. Mike Gikas, a senior editor at Consumer Reports, explains that even when you don't think you're using the phone, the device is running in the background, doing things like retrieving email, updating apps and tracking your location. "And all of these things that happen nonchalantly on your phone, suddenly you'll be paying five, 10, 15 dollars a megabyte, which you can burn through in no time." For example, location-based restaurant reviews - even ones you don't specifically ask for, could cost $2 or $3 each - and you might get half a dozen or more of them in a single day. "The trick for consumers is to be informed." That's William Freedman, an official at the Federal Communications Commission. In 2010, the FCC proposed rules to get wireless carriers to provide timely and effective notice to consumers about these charges. The cell phone companies countered with a voluntary standard, and the federal government said OK.