Oh yeah that.
So far as I know, I haven't spent a $1 on that sort of thing.
(methinks my kitty avatar doth protest too much)
Anyway, I've heard the claim that about 20% of the USA economy is gray or black market. With that much money at stake, it's no surprise people are trying to make money off of it either sideways, or just as gray/black. The Freakonomics guy puts the world number a little higher.