Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
PriceGrabber - Get the lowest prices on computers, electronics, furniture, cameras, clothes and more.
PriceSpy - PriceSpy helps you save money when shopping online.
Slickdeals.net - Slickdeals: The Best Deals, Coupons & Discounts on everything
Keepa - Price history charts and the option to be alerted on price drops for all Amazon sites.
Locotracky amazon price history comparer - We are the amazon price comparator, we inform you every time a product drops in price so you can save on all your purchases.