Approximate street price of 50 grams of cocaine, circa 2007: $5,500 US.
Approximate street price of 50 grams of silk, circa 2009: $27 US.
Just mention that the next time someone tells you that knitting is too expensive.
In fact, I've made this helpful visual aid, which perhaps could be used as part of an anti-drug curriculum:
(It's way better if you click to see it in full-sized glory.)