Splitwise - Splitwise is a free tool for friends and roommates to track bills and other shared expenses, so that everyone gets paid back. On the web, iPhone, and Android!
Lolli - Earn bitcoin when you shop online
/Tab - The simple way to split a bill among friends.
Paribus - Find out for free if online stores owe you a refund!
EquiTable - Split the bill fairly
Earny.co - Win prizes on Amazon purchases