I spend a decent chunk of change on drugs, it's mostly disposable income though. My friends and I always share our shit with each other anyways, so even if your broke you can still party every night. A nice little community of druggard/drunkards.
Maybe 20 - 30 on weed. I only end up smoking when I'm drunk at like 2am. I get xanax and valium for free. Alcohol is another story. I don't think I want to figure that out. I only drink on the weekends but still.