 The auctioneer then serves the highest bidder first, giving them the number of units requested, then the second-highest bidder and so forth until the supply of the commodity is exhausted.All bidders then pay a per unit price equal to the lowest winning bid (the lowest bid out of the buyers who actually received one or more units of the commodity) - regardless of their actual bid.Some variations of this auction have the winners paying the highest losing bid rather than the lowest winning bid.