I had two cases, both concerning Apple gear, where someone was offering the goods at a price to be too good to be true, and after I ordered and paid, in one case the seller returned my money voluntarily and in the other Paypal made good the payment. In both cases these guys were selling the goods they didn't have yet in the expectation of a new product's price falling quickly below their offer price, and then the price didn't fall fast enough. Irritating, and it ties up your money for several weeks, but Ebay and Paypal are pretty good about paying out, and if they fail, your credit company can recover the money from Paypal.