The law of one price doesn't apply - at least for cannabis. According to this survey (pdf), cannabis resin costs twice as much in Manchester as in Liverpool. Which raises the question: why isn't there arbitrage? Why don't traders buy blow from Scousers, drive 35 miles, and sell it to Mancs?
Dillow offers a few possible theories including:
2. Quality differences. Maybe the good is better quality in Manchester.
Perhaps. In college, people we knew had all kinds of theories about where the best stuff was grown. Oddly, most of their reasons were totally contradictory (that place is great, cause it's really cold in the summer... the heat makes for great stuff... you get the point).
Hey, no wonder George Soros is such an advocate of drug decriminalization.