Price Tracker and Price Comparison for many retail stores
Finally, a browser extension that combines price tracking and comparison shopping.
The PriceZombie browser extensions allow you to view price history charts for all stores PriceZombie supports. They also allow you to comparison shop between stores, view sales ranks, and set price drop notifications.
Mozilla Firefox 20+
Apple Safari 6+
Watch the video below for a brief explanation on how the extension works.