They are mostly talking about Reason. [line6.com] It's a software simulator for a bunch of real-life studio hardware that musicians used to have to purchase and hook up and find places to put. So, instead of having to spend $50,000 to outfit a studio with keyboards, synths, patch bays, mixers, effects, compressors, cables, etc., you can simulate it all with Reason for something like $450. But to the people in TFS, this is too much money still, and they would like to make a free equivalent. It's noble, but as others have mentioned there are other options that do not have nearly so polished and authentic sounds and interfaces, but are much cheaper or free.

Rosegarden [rosegardenmusic.com] and Buzztard [buzztard.org] are great for such purposes, and are both open source.