AverageFinder - AverageFinder is an all-in-one product value tracking service for eBay that will provide all the information related to product selling and purchasing.
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Bidvoy - Bidvoy is an effective product value tracking service for eBay that is providing complete requirements as far as auctions are concerned.
Price Snoop - When viewing a product on Amazon, Price Snoop will show you just how much it costs on the other...
StreetPricer - StreetPricer is an ultimate repricing and automated price tracking tool for catalog and non-catalog products that will, in turn, let you find the exact value of the items listed on eBay.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything