If you want to prevent yourself from being scammed learn how to buy and sell on eBay. It's best to start small with less expensive items. Buy, buy and buy some more and then sell a few insignificant cheap things; at a loss just to learn the process. Use that experience to guide you. There is plenty of info already here on scams, search for it. Ebay is work, nobody will do that for you.
.................or are you asking for info on how to be a scammer????????????????????
