Once you find one drug dealer, use him to connect to others. It's really that simple.
Weed's status as the "gateway drug" has been laughed at for decades by now, but the reality is that it is in fact a gateway; not because it makes you want to do harder drugs, but because it puts you in contact with people who through at most a couple of degrees of separation will have them. When you find a weed dealer, just ask, "yo do you know anyone who's got bars?" Chances are they will either directly know a user, dealer, or someone who may know someone else.
In terms of first getting into it, it'll be hard for high inhib anti-socialcels, but there's really no way unless you find someone who unmistakably is a pothead. Weed leaf patch on their backpack or reeking before class or something like that.
and this guy is asking around how to get drugs 
