Whether you're shopping online for inexpensive office supplies or a new sailboat to buy with your annual bonus (AIG employees only), it's smart to do some comparison shopping first. Alas, most comparison shopping is a fairly manual process, even using a price aggregator like Pricegrabber. A better solution: A price checker that automatically tells you the best price for anything you shop for in your Web browser.
Meet InvisibleHand, an add-on for Firefox, Internet Explorer, and Google Chrome. No matter which browser you use, InvisibleHand watches silently and invisibly in the background for you to go shopping. When a product appears on your browser, it lets you know if there's a better price to be had elsewhere.
If you like saving money, you'll like InvisibleHand. It is free and appears to work pretty much instantly: No sooner than I display a product in Amazon or Newegg, for example, a gold bar appears across the top of my browser, letting me know that the same thing is available for 25% less somewhere else. I can click the link to go directly to the cheapest option, or I can see all the alternatives.
InvisibleHand checks over 100 retailers and can even deduce the price of an item if it isn't visible on screen. To quote The Who, "I'd call that a bargain." Especially when it's free.