. >> reporter: suzie kelly is a grandmother from suburban dallas.years ago, she and her husband were thinking about retirement. but, all that changed one when she sat down to watch tv. >> there was a commercial for big fish casino. i thought it was a casino-casino at first, and then i realized it was a game. >> big fish casino. play for fun. ay for free. >> reporter: the game she downloaded is part of a rapidly- growing industry called social casinos that launched on facebook about ten years ago. these apps bundle together games like poker, roulette and slot machines. s( slot machine sound ) kelly's slot machine game was free to play, at first. but, once her free chips ran out, she had to buy more to keep playing. >> i would say that my spending increased to hundreds of dollars and thousands of dollars within the first month. >> reporter: how much could you win playing big fish casino? >> real money? zero. nothing at a. >> reporter: why? >> because they don't pay real money. they only take money, to give you virtual chips to continue t. play on thei