A ‘Product' is used for describing products or services purchased by a customer. It contains all the related pricing rules, specific promotions rules, and any media like images, videos, documents associated with the product. Each Product must have at least one Pricing Rule to define the base cost, and in case of subscription, the billing frequency (e.g. monthly renewal, yearly renewal, etc). Details such as base pricing, trial period, duration of the subscription are inherited from the Pricing Rule when Order is created but can be overridden at the individual Order-level. Any changes to the purchased items, including billing date, and scheduled changes can be managed within the Order. When an invoice is generated for an Order, the required information on the charges is picked from the Product.