1. A method of communications-network shopping by buyers of products and services for purchasing such from sellers, wherein buyers request an automatic reverse auctioneer or auction controller (RAC) to initiate a reverse auction in real time amongst willing sellers and to solicit from automated seller engines (SAEJ) of the sellers their automatic real-time iterative bidding price quotations for such products and services to be returned automatically over the network back to the controller without any manual intervention and under the iterative processing guidance of the controller to assure a best bid price quotation for the buyer; the method comprising, providing a choice of a plurality of options for automated seller engine architecture implementations depending upon the particular application involved, and selected from the group consisting of a parallel processing architecture, a pipeline architecture, a hub and spoke architecture and a hybrid combination of all the above; implementing price managing that is responsible for receiving requests from the controller (RAC) for one or more items that the buyer expresses interest in buying; in the light of received market data and historical prices, configuring the seller engine itself to enter the business objectives of that seller in specific terms of targets or goals that the seller enters; and, based on the type and the values of these goals, automatically optimizing the price at the seller engine for realizing the business objectives of the seller.