Quicken Shopper is a very small program that sits idle in your system tray. When you are on a retailer's Web page that gives the product specs, simply right-click on the Quicken Shopper icon, select compare prices, and voila! It searches for better prices on the Web. The only drawbacks are that it only searches well-known sites, and it sits in the system tray all the time. But I just close it when I don't need it.

Copernic Shopper Basic is a little larger program that stands alone. It does not run constantly in the system tray. It also has more comprehensive, handy features like product reviews and hot deals in addition to comparison shopping. It also has a currency converter to shop sites in foreign countries. I just used it to find reviews of income tax preparation software and it found pertinent reviews very fast.