From Walter Isaacson’s The Innovators:

Stallman’s free software movement was imperfectly named. Its goal was not to insist that all software come free of charge but that it be liberated from any restrictions. “When we call software ‘free,’ we mean that it respects the users’ essential freedoms: the freedom to run it, to study and change it, and to redistribute copies with or without changes,” he repeatedly had to explain. “This is a matter of freedom, not price, so think of ‘free speech,’ not ‘free beer.'”