Selling free software copies

Selling free software copies is a business model firstly used by Richard Stallman and the FSF in the '80 by selling Emacs types [1]. You can simply describe it as selling physical medias with free software. Generally in open source software this is something that every one can do without any restrictions. The physical media is often distributed with other items like manuals, magazines, brochures, etc.

References

1. "About the GNU Project" article by Richard Stallman