One of the best things on the Internet, if you are asking me, is the ability to compare prices easily. Can you think back to pre-Internet times? If you wanted to compare prices, you had to visit local shops individually and look through catalogs to get the best price. Today, all it takes is to visit a price comparison site or to install a browser extension for the same benefits.

InvisibleHand is a browser add-on for Firefox and Google Chrome that helps you in buying a product that you are interested in for the cheapest price. That way, you can save a lot of money, especially if you are buying most items online these days.

The extension supports more than 200 retailers in the United States, United Kingdom and Germany, among them Amazon, and a lot of travel related and airline sites.

The extension scans the price of items on supported product websites, compares that price to their own internal database, and displays better prices in a stripe at the top of the page in the web browser.

In the example above for instance, it found a price that is $79 cheaper than the price on the Amazon website. A click on the link takes users directly to the other shopping site the cheaper price was found on. You still need to check manually for shipping costs and the product description to make sure that you do not buy an inferior product or pay more if shipping and handling are added to the price.

InvisibleHand usually finds more than one retailer, and a click on the retailers button displays a list of all of them in a menu on the original shopping site. Not all prices need to be cheaper though.

The extension supports travel related websites like Expedia, and airline sites as well. It tries to find a cheaper flight or hotel.

Mozilla Firefox users can download and install the extension at the official Mozilla Firefox add-ons repository, Google Chrome users at the Chrome Web Store.