Best price search engine including coupons

Finding a best price available for a selected product, computed including all relevant factors available to the search engine. Searching separately for the product by price, and concurrently, searching for any available coupons or other discounts available for that product from the seller. When obtaining price information, querying for relevant information relating to purchase decisions. Obtaining relevant information from third-party sources. When obtaining discount information, querying for relevant information relating to applicability of that discount. Matching price information with coupon information for each selected requested product, and computing an effective price to the potential buyer. Aggregating the information it obtains, and presenting that aggregated information. Filtering or sorting those results. Maintaining separate pricing information for each product, uniquely identified by a code, in a database entry. Maintaining separate information for each discount. Augmenting this information by hand. Matching pricing information with discount information.