This is a bidding game to do "educated guesses".
Here's how it works:
A user download the app, enters a number to guess how many people will pay during that day, pays $1 to bid.
Let's say he/she said "100 people will bid today". After payment, he/she gets the message "You're the 254th people to bid today." Since it's obvious that more than 254 people will bid that day, he/she can bid again, to fix his guess, and still be in the game.
At the end of the day, owners of 10 bids that are closest to the real number equally shares 80% of the total amount collected. So, let's say 1000 bids have been placed that day. 80%*1000=$800 will be shared by owners of 10 bids and each will get $800/10=$80. (One person can get more than 1 prize if he/she has more than one guess in close numbers)
We'll use in app-purchases to charge users, and I also need a web administrator panel to see bids and owners of those bids, along with their e-mails, so that I can issue their payments. (Payment will...