A multiply-integrated system for inventory, sales, and distribution of products comprises a supplier database, an order database, and a programmed order processor. The supplier database includes inventory/pricing information for multiple independent participating product suppliers, which may include: product manufacturers, distributors, and/or retailers. The order database includes order information received by the multiple participating product suppliers from multiple independent product purchasers. The multiple product purchasers may include any or all of: product manufacturers, distributors, retailers, and/or purchasers. The order processor is linked to the databases and programmed for implementing a multiply-integrated method comprising the steps of: a) receiving/entering pricing/inventory information for the supplier database; b/c) receiving/entering order information for multiple product purchasers into the order database; d) searching for ordered products available from a supplier; e) issuing instructions for delivery of each ordered and located product; f) updating the order database; and g) creating a financial accounting record for delivered products.