a computerized method for exchanging products or services is provided . a first entity referred to as marketmaker specifies one or more terms for a product . the terms comprise product name , grade , quantity range , product &# 39 ; s origin , delivery point , payment term and a price . one or more offers to sell a product are received from a seller . the offer to sell comprises of the following terms : product name , grade , product specifications , origin , producer , quantity , delivery point , delivery period , payment term , invited parties , limitations for buyer counters and price . if the price of any particular sell offer is higher than the price specified by the marketmaker for that particular offer , the offer is rejected and cannot be posted on the exchange . in response to the offer to sell , one or more counter offers to buy from one or more buyers for the product are received . the price of any counter offer to buy from one or more buyers is rejected by the system if the buyer &# 39 ; s price is lower than the price specified by the seller under “ limitations for buyer counters ”. the limitation can be set so that the seller may be open to counter offers only within 1 , 2 or 3 percent of his / her original posted price . an acceptance of at least one of the counter buy offers or a revised offer to sell are received from the seller . at least one acceptance of the revised offer to sell , or a revised counter offer to buy are received from the buyer . the steps of rejecting and accepting are repeated until the exchange closes with the revised offer to sell now the offer to sell and the revised offer to buy now the offer to buy .