  We consider a class of auctions (Lowest Unique Bid Auctions) that have
achieved a considerable success on the Internet. Bids are made in cents (of
euro) and every bidder can bid as many numbers as she wants. The lowest unique
bid wins the auction. Every bid has a fixed cost, and once a participant makes
a bid, she gets to know whether her bid was unique and whether it was the
lowest unique. Information is updated in real time, but every bidder sees only
what's relevant to the bids she made. We show that the observed behavior in
these auctions differs considerably from what theory would prescribe if all
bidders were fully rational. We show that the seller makes money, which would
not be the case with rational bidders, and some bidders win the auctions quite
often. We describe a possible strategy for these bidders.
