WHAT?? Did you ever take a basis Economics class?
It is "supply and demand" that dictate prices, dyammn dude??? Legalities due come into play i.e. (prices in states where MJ is still completely outlawed, low supply ...due to local laws = HIGH prices)
http://economics.about.com/od/demand/ss/black_market_2.htm
marijuana is only legal at the state level.. federally it's still illegal. prices are always determined by supply and demand.. legality affects supply and demand. At the moment, legality is the biggest determinant of supply.