Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Linux users can choose from several big, bulky financial packages to manage their finances, but what about consultants and freelancers who just need to whip out a few basic invoices by the end of the month? For that niche, Simple Invoices, a Web-based, GPLed invoicing system, is a winner for folks with a bit of tech savvy.
Simple Invoices requires Apache, MySQL, PHP with support for XSL (PHP5) or XSLT (PHP4), and GD2, and you need to give PHP a minimum of 24MB of memory if you want to have all of Simple Invoice's features available. PHP's default is 8MB, so this may put Simple Invoices out of the question for those on a shared hosting environment.
It took me about 45 minutes to set up Simple Invoices, and that included the time it took to skim the documentation and install the requirements that were not already available on my Ubuntu Dapper server. Overall, the Simple Invoices documentation is well done, but the installation instructions give some very bad advice.