We don't have to give K-Mart $10 first, before they decide to price the widget at $9.95 or $5.

And particularly on auctions of reasonably rare items, it's reasonable for a person to bid a large amount with the idea that if they lose the auction then they may not get another chance at the item, and therefore will pay "whatever it costs." But that is based on the assumption that "what it costs" will be one bid increment over what another collector is willing to pay. For a seller to start with a low opening bid, and then manipulate the lowest price through a secret shill, is dishonest, unscoupulous, and akin to theft.