there are some really simple rules for any sort of online auction or dealings.
1 - do not buy anything worth more than you would be prepared to loose.
2 - always, always, ALWAYS pay with something like a credit card or paypal, so you have some recourse to getting your money back.
3 - steer clear of people with bad or little feedback.
I am always amazed by people who are 'scammed' on ebay, because the have paid somene $1500 in cash, from someone with bad or little feedback.
Not saying they deserve to be ripped off, but I think they are certiainly as much victims of their own stupidity.