17. The system of claim 15 , wherein the discount rules are further configured for determining a total discount value for a plurality of applicable discount types, wherein the discount rules are configured for executing the discount rules to automatically determine the total discount value associated with the purchase order.
15. A system comprising: a server; a plurality of provider computers operatively coupled with the server and offering products for sale via the server; a plurality of client devices operatively coupled with the server, wherein the server is configured to: send a reclusive rules engine to a client device from the plurality of client devices, wherein the rules engine comprises a set of discount rules configured for automatically determining a purchase order discount from a coupon code when a purchase order is made and when a purchase order is modified, and wherein execution of the rules engine comprises: recursively evaluate a first set of rules for determining an applicability of the purchase order discount; recursively evaluate second set of rules for determining a discount value relating to an applicable discount; recursively evaluate the first set of rules and the second set of rules by performing an automatic process that recursively calls itself; receive a purchase order placed by a user of the client device along with a coupon code; receive the purchase order discount from the client device for the purchase order as automatically determined by the rules engine upon placement of a purchase order; applying the discount for the purchase order without independently determining the discount; relying on the determination of the rules engine; apply the discount without independently determining the purchase order discount; and process the purchase order along with the purchase order discount.