Free Software refers to freedom, not price. This "free" is the F in FOSS. Paid free software is still free as in freedom and thus FOSS. Since the free software definition and the open source definition more or less overlap, very little is "OSS but not FOSS" even if it is paid.
I understand this notion, I simply was trying to specify which of these software you can use without paying anything and thus have a lower barrier of entry since it would be inefficient to explain this at the same time.