Actually, thinking about this further, even free of charge could be problematic. I can 100% see a "cancer research and spiritual healing" clinic popping up that uses the promise is a cure as a way to get someone in the door so they can later be sold on energy healing to increase effectivity of the sugar pill they give away.
Depends on how it's marketed. As long as they avoid making specific health claims (say "boost immune function" instead of "cures disease X") they can get away with it. If it's "homeopathic" they can even be sold on the same shelves as actual medicine, with similar looking labels.
Ish. You can't say that a pill or treatment cures cancer if there's no evidence to back that up. Of course in private I'm sure that's said all the time.
My concern with lowering the bar for advertising such services is it makes it easier for someone to jump in with "Our clinic is actively researching cancer treatments and offers free experimental drugs".
Fraudsters simply love preying on the desprate.