I've heard some good and some bad stories regarding PayPal.
In regards to a website, I still stick with my previous comment but that's only cause I'd hate to see sources, even the one's that sell non-controlled items, get busted. Some of the sites previously mentioned are great sites but all it takes is for the feds to get bored and they'll all be down in a matter of a week. At least if you stick with e-mail you won't have to worry about this as much, if it was to come.