A reverse auction method and system are provided for non-commodity goods, services, and systems. A purchaser creates a description of goods, services and/or systems required by the purchaser and sends the description to a number of potential vendors. In response, the vendors prepare an offer template provided by the purchaser showing the components and services proposed by each vendor and prices associated therewith for supplying the required goods, services or systems. The proposal/offer from each vendor is adjusted to ensure that the offer from each vendor will produce a similar and acceptable result. A downward bidding increments session sets downward bidding that is allowed by the vendor during a subsequent auction process. Each vendor executes a contract that is binding on the vendor if the vendor's bid during a subsequent auction process is accepted as the lowest bid. An auction is held in which each vendor bids against other vendors using the pre-negotiated downward bidding increments.