Set a goal with your friends. The app keeps score.

1. 1
   Agree on the goal with the group. Say, under 2h of screen time a day, with $25 on the line.
2. 2
   Send your proof. A screenshot or a photo, and the group checks it.
3. 3
   Whoever fails pays whoever keeps it. In money or a forfeit, like buying the pizza. Whoever keeps it never pays.

The money goes straight from one friend to another. The app never touches it.