Buying generic prescriptions without a prescription

Has anyone ever done this? I've seen a lot of places on the internet that offer Valium, Xanax, Vicodin, all kinds of stuff for purchase without a prescription. They call it generic, but I've seen a few that say they use the exact same ingredients like hydrocodone, etc.. Just wondering if this is a scam or what. Thanks.

they are mostly scams. there are a few that aren't, mostly based in little third world countries, but i'm not going to give them away :P