Evenfy - A free tool to manage household IOUs with roommates, split bills and track group expenses so that everyone gets paid back. On the web, iPhone, and Android.

Monzia - Monzia can help you save money, relieve stress and make time for the fun things in life.

Splid - Splid helps friends manage their money.

Grisbi - Accounting for everyone !

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!

Ledger-cli.org - Ledger is a powerful, double-entry accounting system that is accessed from the UNIX command-line.