Scavenger Hunt by SPARE.

Coins will be dropped in certain areas.
To find them, get within 10 meters of a coin, and tap it on the map. It will then appear somewhere around you.
To collect a coin, locate it in your surroundings, and drag it in your wallet.
Congratulations, you just collected the dollar value that coin is worth!
To redeem your coin for cash, open your wallet, and go to the location listed for that coin.