Not really, but they are available at times. I know this from first hand experience. I spent four months in in 2006 in the Arizona DOC for DUI. (Don't worry, I didn't hurt anybody or hit anything) My cellmate (head peckerwood/white boy/biker dude) controlled over half of the drug traffic in the prison. The brothers and chicanos controlled the rest. The stuff was muled in on weekend visits from family or friends, shoved up an ass, and brought into general population. Sunday nights were really interesting at times. Walking through the yard and smelling the air you'd think a rope factory was burning. Cocaine, meth, heroine, whatever could also be had at a very hefty price. A few of the guards (making about $11 an hour) would also supplement their income by smuggling in illegal drugs. Since I wasn't doing drugs there, my hustle was to sell my clean urine for other inmates to pass the random drug tests. $10 (not cash, but commissary purchases) for a small shampoo bottle filled with my drug free pee. I didn't get rich, but I could keep myself stocked up with snacks, sodas, and tobacco, which is the currency of choice.