Startup Idea : Cyber Treasure

You know that happy feeling you get when you find money on the ground? I want to recreate that with an app. This app would hide rewards, typically in the form of cash, in different parts throughout a city. Whenever a user gets to the location where the treasure, they get the reward which can range within $1-$10. The money would then get debited to the users account to withdraw at any time. Revenue would come in the form of advertisements or corporate sponsors who give out gift cards on the app. (user findings of cash would be expensed)