1. A method of an exchange computer executing a purchase transaction with a user computer, a merchant computer, and an issuer computer, comprising: an exchange computer receiving from a merchant computer a price discount schedule that specifies price discounts to be automatically generated by the exchange computer as a function of elapsed time that an item is available for purchase, wherein the price discount that is applied to the item will increase as the length of time that the item is available for purchase increases; the exchange computer automatically generating a price discount in accordance with the price discount schedule as a function of elapsed time that the item is available for purchase and offering the item for sale to a user computer using the generated price discount, the exchange computer receiving from the user computer a request to purchase the item with the generated price discount and a selection of a user reward account stored on an issuer computer and a quantity of reward points to be redeemed from the user reward account towards payment of the purchase price; and the exchange computer executing a purchase transaction for the item from the merchant computer using at least the quantity of reward points from the user reward account selected by the user computer by the exchange computer requesting the issuer computer to reduce the user reward account by the quantity of reward points selected by the user for redemption towards purchase of the item from the merchant computer and the exchange computer requesting the issuer computer to convey consideration directly to the merchant computer corresponding to the quantity of reward points reduced in the user reward account.