Money Manager Ex is a free, open-source, cross-platform, easy-to-use personal 
finance software. It primarily helps organize one's finances and keeps track 
of where, when and how the money goes.

MMEX includes all the basic features that 90% of users would want to see in a
personal finance application. The design goals are to concentrate on simplicity
and user-friendliness - something one can use everyday.

Supported platforms:

MS Windows: 95, 98, ME, 2000, NT, XP, 7.
        ANSI and Unicode builds; x86, x64, ia64 versions available.

Unixes: almost any Unix workstation with GTK+ 2.0 and above.
Mac: Mac OS 8.6/9.x (eg. Classic) or Mac OS X 10.x.