InvisibleHand and PriceBlink are free extensions for your Firefox, Safari or Chrome browser that help shoppers find the best online deals. Oh, and PriceBlink is available for the iPad too. Both work to automatically compare prices and find coupons from 100’s of retailers when you are shopping online. You can watch demo videos for PriceBlink and InvisibleHand to see how they work. Get more details and my quick review after using both browser extensions in the article, “How to Find Coupons Automatically When Shopping Online”.