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!
Splitz - Split group expenses with ease
Dinngo - Splitting payments the fun and easy way
Mockoon - Mock servers in seconds
/Tab - The simple way to split a bill among friends.
down-river.net - Outdoor gear: open box / used.