The thing is that it is not just Tor that you'd need. I also used Private Tunnel, and you'll have to have bitcoins to make any purchase. So for the casual buyer the hassle is too much.
Depends on the legality of what you are looking for as well, obviously. At most I'd get a small fine for buying roids here, so worth the risk.
If you're using Tor for really illegal searches, then I would take even more extreme security measures. Buying a second-hand laptop from a flea market, only using it for those searches, only from free wifi places far from home, etc. I wouldn't be diligent enough to have literally nothing personal on that laptop.
