I've written a web crawler for a fortune 20 company, while I was in a research group at said company. I know exactly what would be involved. Storing prices with some small meta data is much much cheaper than storing full pages in the form of a search index. Scraping a discrete list of sites is far far easier and cheaper than writing a crawler robust enough to attempt to crawl arbitrary pages on the internet. Not only that, many retailers have APIs these days so a scraper wouldn't be needed for many of them, and reading from an API is something a novice programmer could do in less than an hour per retailer.

One of my close friends worked at pricegrabber for years, and the statement "all they do is create an index of online prices" is completely false.

Your continual use of ad hominem speaks volumes, and is your attempt to hide a lack of hard numbers.