Having a free Unix-like operating system like Linux is Really Nice (TM). All the corresponding source code is publicly available, wither via FTP, on CD-ROMs or in specialized BBSes.
"Free Software", however, does not necessarily mean that the software is available for free -- it just implies what you are allowed to do with it once you have it. This is the interpretation of the term "Free Software" pushed by the Free Software Foundation, especially by Richard Stallman (the founder of the GNU project and the developer of GNU Emacs). My opinion is in perfect sync with that. However when it comes to widespread commercial use of the free operating system we are talking about, this is virtually impossible without commercial applications running on it.