The present invention is directed to providing a method, apparatus and system for a unified product purchasing service and order injection system. More specifically, the present invention is directed to providing a shopping service that obtains products for a consumer across many different merchant and supplier sites while maintaining a consistent user interface for the consumer no matter which merchant provides the products. In particular, the present invention allows a consumer to search for, compare prices and order products from many different merchants located on the Internet. The consumer completes their shopping on the shopping site provided by the present invention and is not directed to another merchant's site to complete an order.