Mpire.com

This is a shopping search engine on steroids. Not only will it give you a list of links to where to buy that 32-in. LCD TV, if you click on Show Product Details, it will display a pricing chart that shows whether the price is trending up or down, at both retail and at auction, so you can decide if it's the right time to buy. (Farecast does the chart thing with airfares.) The "shopping companion" browser plug-in, a free download, is handy to use when you are shopping at other sites; it shows what other etailers are charging for the item you're looking at, so you can be sure to get the best deal. Soon it will also show how consumers rated the product on Epinions and Amazon. Another shopping search engine worth trying: TheFind.com. So far this site has indexed more than 150 million products offered by 55,000 online stores, from mom-and-pop Web shops to major e-tailers like Amazon.com, and it doesn't accept payment from merchants for top placement in its search results.