Is yet another option but strictly used refers to addition of an current constituent (which has been shed in the course of processing such as). Agree with Jimi that by far the most correct antonym for "free of charge" is "available for purchase." But, "acquired" or "priced" could do the https://docs.google.com/document/d/e/2PACX-1vTrVZBlXQ93932G_bwrC4lvRYQ9hi-BzXccPrzn0BlNgJSiUFDowMTDkoAEyzcR1K8T6eyq9rdwdvgC/pub