Google - Product Search
Product Search - Google Product Search is different from most other price comparison services in that it neither charges any fees for listings, nor accepts payment for products to show up first. Also, it makes no commission on sales. Any company can submit individual product information via Google Base[1] or can bulk submit items for inclusion [2]. Notably, advertising space is available for purchase to be displayed in Product Search in the form of an AdWords ad, similar to those in other parts of the Google network.