there was a huge bandwagon on these types of sites a while ago
it was a bitch and a half and felt like most of the "deals" were scams, but by being hyper-vigiliant i ended up getting my gf an ibook for $38 total. i was the hero for christmas but i had to fight like hell to get it.
FOR EXAMPLE:
one site was some OTB thing i think. it was, FREE TRIAL, CANCEL WITHIN 24 HOURS....or you get charged $49.95. so i sign up...and i have a hunch, so i pay close attention to the screen. suddenly i'm redirected to a page with some weird account number on it. i hit printscreen just on a hunch. sure enough, i'm redirected to another site 5 SECONDS LATER.
when i go to cancel the next day, it asks for that number. if i hadn't taken a screenshot i would have been out $50