We have already touched on how open source software can be used by businesses for a whole variety of applications, including financial applications. So if open source financial software are secure enough for businesses, then you can bet that there are great open source software you can use to help you with your personal finance.
KMyMoney is one of the best personal finance manager for Linux users, although versions for Mac and Windows users are also available. It is licensed under the GNU General Public License and it is FREE. Unlike many free personal finance software, KMyMoney is not a crippled version and has tons of features and is even often compared to the popular (not free and not open source) personal finance software, Quicken.
KMyMoney has all the bells and whistles of a commercial personal finance software including expense categorization, multiple currency support, intuitive budgeting, credit card and debt tracking, report generation, and even online banking support via QIF, OFX and HBCI. Best of all, it is easy to use, especially if you are already familiar with the usual personal finance apps.
Image via KMyMoney