Price comparison script for selected online shops

Hello, I am looking for someone who can make me a price comparison script for online shops. I only want to add shops and the "scripts" hast to crawl the pages for product and price and hast to save it in the database. It means that the script has to look for product name on the page maybe about some tags given and get the product name and price. product details and images will be good, too. Waiting for your messages and ideas. Best regards