A while back we did a review of an interesting addon for Firefox called InvisibleHand - a tool that compares prices across dozens of different online retailers and displays the best offer available for the item you are currently looking.
A new beta version 1.8 is out and we have 200 invites to give away! To try the beta just go to this page and enter the invite code “invisibleInstant”.
The new version integrates with Google search showing you the cheapest prices when you search for a product. This allows you to view the cheapest offers even before you visit an online retailer’s page. And unlike other price comparison sites which uses out-of-date product prices, InvisibleHand gets those prices in real-time.
The new beta also has an enhanced notifications system which is more discreet, and the responsiveness of the addon has improved.
Current limitation: Not all regional Google search sites are supported. Presently supported for Google.com or Google.co.uk.