Maybe you’ve heard that today is Black Friday, so named because it’s the biggest shopping day of the year, the day that many retailers go from being in the “red” to being in the “black”.

Personally, I’d rather eat nails than go out shopping today, but fortunately, many online retailers offer great deals too, making your holiday shopping far less painful. Some notable retailers to check out if you’re in the market for new equipment or software are Apple,, and Amazon.

But how do you know if you’re getting the best deal, even if it’s a “Black Friday special”? There are comparison sites you can visit, but there is an easier way. There is a feature that was introduced in Safari v.5.0 called “Safari Extensions” that allows you to easily introduce plug-ins to Safari that add to its functionality. You can see a list of, and easily install, these extensions by going to the Safari menu and choosing “Safari Extensions Gallery”.

One such extension is InvisibleHand. This neat gizmo will stay silent until you view a page with product information. It will then show you the best price for that product, the percent you’d save (if any), and give you a link to that vendor along with prices and links to other competing vendors.

It’s important to note that it doesn’t work with all products and pages, but where it does, it’s quite handy.

Getting back to Safari Extensions in general, explore the gallery for items that might interest you. This is an up-to-now little-known feature of Safari that is very useful, but be careful. As with all software, some have bugs and will cause odd problems. Feel free to experiment, but if you need to disable or uninstall an extension, you can do so from the Safari Preferences.

[Written by Kem Tekinay]