tuxtrans, a Desktop GNU/Linux System developed for translators, is not only completely free (based on free software, open source) but is a truly complete system. It is an operating system with all needed software for the freelance translator or any other translator.
Interesting article: Why you should use free software
Besides the obligatory CAT tools (Heartsome Translation Studio & Heartsome TMX Editor, OmegaT) there are office tools like LibreOffice, email tools like Thunderbird (plus Lightning for the calendar features), the Machine Translation software Aperture, software translation tools like POEdit, Virtaal, and much more. Even if you have to use some Windows tools you don’t need to worry, the Wine emulator is able to execute most Windows software. Click here for a complete list of software available on tuxtrans.
tuxtrans does not need the fastest machine on earth either. We tested it on a five year old laptop with 8 MB RAM, an Intel Core i5 processor and 750 MB hard drive. Even though we did not test every single software in depth the result was encouraging. The speed was decent. Only if you run tuxtrans from a Live CD or bootable USB stick you will, of course, have to deal with a slower system but it is still not a big deal if you just want to test the software a little.