1. A method comprising: receiving, over the Internet and from a customer of a web site available via the Internet, a request to display a type of product; selecting, by use of a processor of a computing device operable to facilitate the customer's interaction with the web site, a substitute product for the product from a plurality of substitute products for the product, in which a plurality of manufacturers have agreed to pay for display of a respective substitute product of the plurality of substitute products, in which selecting is based directly on expected revenue from the mere display of the selected substitute product; displaying, by use of the processor and on the web site, the substitute product adjacent to at least one other product which corresponds to the type of product; receiving, over the Internet and from the customer, a selection of the substitute product; and allowing the customer to purchase the substitute product.