Google has a product search feature in beta now. This may be useful with the holidays coming up. I did a search for the Beatles “Love” CD and noticed quite a wide disparity in prices from $12 to $22.50.
The gallery view makes it easy to compare. You can click through the “Reviews” links to see what (hopefully) real people say about the product you are considering. They also have information about local stores where you can buy the product you have searched on. It looks like Bing has developed some nice product search capabilities as well.