In lowest unique bid auctions, N players bid for an item. The winner is
whoever places the \emph{lowest} bid, provided that it is also unique. We
derive an analytical expression for the equilibrium distribution of the game as
a function of N and study its properties, which are then compared with a large
dataset of internet auctions. The empirical collective strategy reproduces the
theoretical equilibrium with striking accuracy for small N, while for larger N
the quality of the fit deteriorates.