A promotion price adjustment system of the present application utilizes improved data definitions, caching, and a combination of online and offline processing to increase the efficiency and speed of applying promotional discounts in electronic retail systems. The system performs an offline batch process on a product catalog to generate a predetermined mapping between products in the catalog and candidate promotions. When checkout of a product in a virtual shopping cart is initiated, the product's candidate promotions are obtained from the predetermined mapping. Each of those candidate promotions is then evaluated against the properties of the virtual shopping cart to determine which of those candidate promotions are eligible for application. Any eligible promotions may serve as a basis for applying price discounts to the virtual shopping cart.