Software which is distributed for zero price is often termed "free", but that English word is mostly associated with liberty. A definition for FreeSoftware already exists; it is confusing to use the word "free" to refer to a restrictively-licensed program that merely has a zero price tag.
Note that whether a particular program is zero cost is a function of an individual act of distribution -- the same identical program may be distributed to different people, or at different times, for various prices, including zero.
In contrast, whether a program is FreeSoftware is a function of whether its users are able to exercise their freedoms.