Please tell me how shill bidders get into a bidding war against each other? A shill bid is a bid that is placed on the behalf of the seller to raise the price. A person that is NOT working on behalf of the seller to raise the price is not a shill. There are people who bid on items to raise the price but do not really want to buy that item as they may have the same item for sale so they raise the price of all the similar items, but they must be careful they don't win.