Personally I wouldn't be so paranoid.
All I would make sure is that it works. The price is good, but not mind blowing that it sets off alarm bells. I really wouldn't freak out just yet.
As I said I would definitely make sure it works though. And trust your gut, I am sure you are not a dumbass. If you see the guy is a Nigerian carry the PS3 in a checkers packet then um ya there is something not lekker.
And take a mate with you. Easy.