this is ebays definition of shill bidding:

Shill Bidding is bidding that artificially increases an item’s price or apparent desirability, or bidding by individuals with a level of access to the seller’s item information not available to the general Community. Shill bidding is prohibited on eBay.

Because family members, roommates and employees of sellers have a level of access to item information which is not available to the general Community, they are not permitted to bid on items offered by the seller–even if their sole intent is to purchase the item. Family members, roommates or employees may purchase items from a seller without violating this policy simply by using purchase options–such as Buy It Now–which do not involve bidding.

SO!!! shill bidding is basically the seller or firend or family bidding on the sellers just to increase the price.

HERE AN EXAMPLE !!! you are trying to bid on an item and win it and you get outbid and the auction ends. you have lost. very shortly after the seller offers you a second chance to buy the item (second chance offer). this could be an indication that the seller bid on thier own item, won thier own item and now wants to try to sell it to the next highest bidders. this is not always the case but beware expecially if it is not an item that the seller is likely to have duplicates of in stock. (like a rare item or collectable).

please click if you have found this helpfull. it will give me more motive to show you more ways to avoid scams and to save money!!!! thanks, atariaction