Sports betting ads are everywhere. Some worry gamblers will pay a steep price

Sports betting is exploding across the U.S., but how companies advertise remains largely unregulated. (Kyle Ellingson for NPR)

A new era of legalized betting is taking root across the U.S., one that is radically reshaping what it means to watch professional and collegiate sports.

For many fans, the days of the once-a-year Super Bowl office pool are a distant memory. Betting on sports in much of the country is now as easy as tapping an app on your phone.