and good mornings. pampers. cause it s your birthday cause it s your birthday it s your birthday it s your birthday we are just back from the beach and a dip after that steamy segment. yeah. you re still wet. still wet. try froging to dry off. the swimsuits we saw can be pretty unforgiving to some bodies on the beach. you trying to say something? no, this is a buff bod over here. sarcasm there. a new way to help you get in shape. an app pays you to do it. abc s becky worley has the details. reporter: after three babies in two years, tiffany snook hit
there is two ways. you either have to actually go to the gym and check in with the app or can be counted on steps on your fitbit. reporter: the app uses the gps in your phone to check in at a known gym and monitor how long you stay. or you can track steps taken with a fitness band or miles run again with the phone s gps. each time you go to the gym, you check in and it uses the gps in your phone to verify you re really there. tiffany walked away with $41 in her pocket. it s nice to have an income. where i say this is mine. i made that all by myself. reporter: the money she gained is great. but the weight she has lost. priceless. becky worley, abc news, napa, california. well, money is a motivator. and so is going to the beach. oh, you know about that. i do know about that because i spend a lot of time there pumping iron. you ve got the better body. i don t know about that. we are partners in crime.
her all-time high, 225 pounds. i didn t have energy. and i didn t want to get on the floor and play with them. i was unhappy with myself. reporter: but getting on an exercise program. never, i had never exercise in my life. reporter: so she turned to pact. it is an app that uses money to motivate your workouts. weight has a secret weapon. pact. reporter: and it worked. tiffany lost 90 pounds. it seemed like it was just for me. it was made for me. i realized i could make money at it. reporter: you give the app your credit card or paypal information. each week you pledge you will do a certain number of workouts and say what penalty you will pay if you miss one. that s right. minimum $5 fine is assessed if you skip the gym. but if you make all the workouts, your reward money comes from the pot of fines from people who fail to honor their pact. how does the app know you have gone for a walk or been to the gym and didn t say you worked out.