A mountebank has a talent for tricking people into buying things, like the mountebank who charms women into buying "magic beauty pills" for hundreds of dollars, though they are just ordinary vitamins you can buy anywhere.
Mountebank, pronounced "MOUN-tih-bank," has an interesting origin, in the Italian phrase "monta in banco." It describes a "doctor" who would "mount a bench" in the marketplace. Standing a bit higher than the crowd enabled people to hear his sales pitch and see the potions and powders he claimed were medical cures that never failed — claims as bogus as his credentials. A mountebank is a fast-talking crook pretending to be an expert.