All commercial UNIX vendors sell their compilers. Even in Solaris case, the EULA does not allow you to sell software done with their "free" compiler.
Intel compilers are not free for Mac OS X and Windows.
All the SDKs for game development from the console owners are not free.
The express editions of Visual Studio compilers are limited in which optimizations they offer, libraries and supported processor targets.
The compilers from Portland group for HPC.
The compilers from CodePlay for the game industry.
Even the compilers from Apple can be said that they are not free, after all you're paying indirectly for them when you buy a Mac Developer's license.