In a multi-unit combinatorial auction, reverse auction, or exchange, a number of bids can be received, with each bid including one or more items and for each item a desired quantity thereof. Each bid also includes a price. A number of unique combinations of bids can be formed from the received bids, and the one combination of bids which represents the best value in terms of an auction setting, a reverse auction setting and/or an exchange setting can be determined. Thereafter, the bids forming this combination can be declared the winning bids of the auction, reverse auction or exchange.