"It's time we corrected a common misperception: There's no law
against selling free software. Really -- read GNU's General Public
License."
"In fact, Free Software Foundation president Richard Stallman
has supported himself and the foundation for years selling free
software."
"The key to success for free software firms is writing a
warranty that both limits corporate liability and attracts
customers. That, and wrapping an effect service and support
offering around GPL'ed products."