The idea of free software is a popular topic thanks to the work of the Free Software Foundation (FSF) headed by Richard Stallman. Their main mission is to propogate the concept. As a result of this, you have people around the world delivering free seminars and other campaigns to publish the idea of free software.
Later in this blog you will find posts dealing with varoius issues dealing with free software, some definitions, and my personal views.
On a last note I'd rather say that free software isn't about software that is sold free. Selling it for free is a personal or an organisational decision. The meaning of "free" in it says that after acquiring this software you have realtively more freedom as against similiar proprietary software packages.
Ultimately free software is about freedom, not price