The invention relates to computer-implemented systems and methods for creating a reverse auction on a realty related item. A buyer uses a computer-system programmed with an algorithm for creating the reverse auction and one or more sellers use a computer-system programmed with an algorithm to submit bid items. The set of procedures comprises that (1) the seller' s bid item can individually undergo forward bidding by other buyers to form a forward auction on the item and (2) the series of forward biddings of one or more bid items continuously updates the bid information in the reverse auction.