Law enforcement are full of shit.  They often quote drugs as being ridiculously more expensive than they are, my foaf used to see the prices they throw out when he knew how much these things costed and think whaaaat?!  I think dealers just sense that they're suckers because of their eagerness to buy, so massively overcharge them... then get busted so the joke's on them.

I suspect they use the threhold dose for their figures to sensationalise.