The word "free" is used in several ways depending on the context. Sometimes the word "free" is used in the context of people being free to do something. At Wikimedia wiki projects such as Wikiversity, people are free to copy and re-use the text of the website content according to the GFDL. An important part of the GFDL is that commercial re-use is allowed, so there is a sense in which "free use" of Wikiversity content might involve having to pay for access to that content. For example, I might put some Wikiversity content on a DVD and sell the DVD. The DVD would not be free in the sense of "no cost" but the information on the DVD would still be free in the sense that people are free to copy and re-use it.
Reading: Gratis versus Libre at Wikipedia
free/gratis: this is a way of indicating "free in the sense of no cost"
free/libre: this is a way of indicating "free in the sense of freedom from copyright restrictions"