A system, and associated method, aggregates, optimizes, allocates, and prices products orders by members of buying clubs wherein a network interconnects a master computer having a database to a plurality of buyer computers connected to the network for data communication with said master computer, each of which buyer computers is operable by at least one respective buyer of at least one buying club, and is configured for generating to the master computer data defining orders of products placed by said respective buyers. Computer program code executable by the master computer compiles each of the respective orders into an aggregate order, and, with reference to data structures of said products, inventory, optimization criteria, and orders of all buyers including any specified minimum, preferred and maximum specified units, generates optimized orders and allocations to achieve improved outcomes for buyers, thereby facilitating purchasing and commerce by and between members, buying clubs, and suppliers.