A method of transacting sales over a computerized network correlates in a first database record a first product and a plurality of first purchasers to form a pool; further correlates a plurality of second purchasers; issues an offer to a vendor of the first product; and consummates a transaction between the vendor and the first and second purchasers. The offer is issued to the vendor responsive to a time rate of accumulation of buyers in the pool. A first commitment price for buyers is responsive to historical sales performance of the first product; a price trend of an article similar to the first article; or a price trend of the first article itself over time. A second product desired to be purchased by a first purchaser is defined, and an offer is made to a vendor for the purchase of the second product.