With Dutch decriminalized laws on selling "soft drugs" (weed and hashj) the market for it is actually working with competition (most idiotic thing is that growing is still very illegal in NL and actively craced down on by police).
With sales out in the open much about the prices has to do with quality. I live in a city with around 100k population and we have around 10 coffeeshops operating in the area.
Weed goes from cheap: 4-5 euros to expensive 10 Euro's per gram.
Hashj (mostly smuggled from Marocco or Afghanistan) goes for 7 euro's till 14 euro's per gram.
In Vancouver the prices vary wildly.
We're already going through the transition to legal weed, even if technically it's not legal yet.
Good green is usually $100-200/oz. (70-140 Euros, or 75-150 Freedom-dollars).