One infamous auction during Roman times is described by Edward Gibbon in his Decline and Fall of the Roman Empire (1776). When the Praetorian Guard killed the Roman emperor Pertinax on March 28, 193 A.D., they sold the Roman Empire itself to the highest bidder, the wealthy senator Didius Julianus, who "rose at once to the sum of six thousand two hundred and fifty drachms, or upwards of two hundred pounds sterling" per man…The new emperor lasted only two months, but did manage to strike some very handsome coins.
That is from the new Snipers, Shills, and Sharks: Ebay and Human Behavior, by Ken Steiglitz. Here is the book’s home page. Here is more background on the Roman auction.