I'll be short and to the point. My experience was not unique in the town where I grew up.
It was pretty hard to buy alcohol. Vendors wouldn't sell, so you had to steal it or find a homeless guy to buy it for you. I didn't smoke cigarettes, but my friends did, and many were the time it was my turn in the rotation, going from gas station to gas station, to try to get some cigs for the group.
Other things were easier to find. There aren't too many back alley booze salesmen. Let me just go over the list of drugs I used, not infrequently, before I ever started drinking. When I was a teenager.
Ecstasy (what's sold as ecstasy on the street, in various mixtures)
I even knew a girl whose first drug experience was LSD at age twelve.
Now, admittedly I was a wild child. It's my view that some of this was ok. A lot of it wasn't. I never became dependent on anything, but some of my friends did. My point is this: I think the drug war drives kids to take wilder drugs than they might otherwise. And I think that's kind of fucked up. I don't have statistics. I certainly lied about my drug use when they passed those 'anonymous' surveys around our classrooms. I expect most students are smart enough to do the same.