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!
QuickBudget - Quickly review your monthly expenses. Free and 100% private!
Kittysplit - The easiest way of sharing costs with a group of friends
5coins - A simple app to track your daily expenses
ihatemoney - Manage your shared expenses, easily
SplittyPie - Create event, add users and their expenses.