There's an auction site I use that is run by an online retailer, and some of the higher-end items routinely get bid higher than they could just click over to the retail site and buy the item outright. Part of it might be chalked up to sloppy research and operator error, they either don't know they're over-bidding or they just clicked the wrong maximum bid, but I think a lot of it is just getting caught up in the competitive feeding frenzy. Whatever the cause, it happens every damned day.