The demand aggregation system includes deal room sponsored by a third party host. The third party host facilitates commercial transactions between a plurality of buyers and at least one seller. In exchange for sponsorship of such a deal room, the third party host can receive an incentive such as a percentage of sales, seller discount or the like. Furthermore, mechanisms are provided to aid discovery of sellers and/or offers that can be included in a group buying event for a buying group. The buying group receives a greater discount as the total purchase amount in the group buying event increases.