Why would people sell regular mushrooms laced with a substance that is in all likelihood harder to get and more expensive than magic mushrooms which can be grown by anyone?
http://en.wikipedia.org/wiki/Lysergic_acid_diethylamide#Econ...
That said I know that the magic mushrooms pricing was thought by everyone to be massively inflated due to lack of supply at that time, so possibly it was a temporary situation.