A search engine system assists users in locating web pages from which user-specified products can be purchased. Web pages located by a crawler program are scored, based on a set of criteria, according to likelihood of including a product offering. A query server accesses an index of the scored web pages to locate pages that are both responsive to a user's search query and likely to include a product offering. In one embodiment, the responsive web pages are listed on a composite search results page together with responsive products included in a product catalog.