Pennies - Incredibly simple personal budgeting app for iOS
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!
Budgt - Track your ramen spending (iOS)
Splittable - Shared living made simple
Unspent - Track your spending money. Keep it simple.
EquiTable - Split the bill fairly