Build a Website for Price Comparison Search Engine

Need a website that searches a number of specific websites in an industry and lists the products based on a search (200 or so products). I would prefer if a web scraping service that searches through each retailers website (there are only 20-50 or so) and can compile all the results on the website from a search of the product (search engine style). Also an API if possible that other retailers can log into and enter prices of their own on a weekly basis would be beneficial. Example websites include: 1. [login to view URL] - Using the codeigniter php framework, jQuery, PHP and MySQL all running on Cent OS. - I like the trend of the prices shown here and the range in the past for the product - Like the layout and design overall 2. [login to view URL] - Basic design but very good at grabbing data from websites somehow. Not sure how they do this. - There is some discussion here of how they may do it ([login to view URL]) 3. [login to view URL] - Not for products but for flights Would be good to also set up a price alert system where people can be notified of a price that is at a certain level (for members). Happy if only the coding is performed for this website with a very basic design. The coding and function is more important than the design (much like the [login to view URL] example). Will pay according the level of function and complexity. Would also be interested in an Android and iPhone app with the same system. Thank you.