Shoptimate - Use the Shoptimate extensions to compare the price without any click. When you browse an item on a online store, a bar shows up at the top to tell you if the exact same item can be found cheaper elsewhere. Including shipping costs
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Shopzilla - Shop smart and shop fast at Shopzilla!
Price Snoop - When viewing a product on Amazon, Price Snoop will show you just how much it costs on the other...
Invisible Hand - InvisibleHand gets you the lowest price on shopping and flights.
QuickMark - QuickMark makes everything possible.