I have news for you: opiates cost far more on the street than they do in a pharmacy. That excuse won't fly. As someone mentioned, a single vicodin can go for $20 in the open market; "oxys" can cost upwards of $40 for one pill.
Vicodin on the street typically sells for $3 or $4 a pill. Lorcet, which includes a bit more hydrocodone, typically sells for about $5. Oxycontin, depending on the strength, typically sells for $8-$15.
They are wonder drugs. Not for "partying," but for relieving pain, both physical and psychic.