PriceCute - Keep up with your competition's pricing on Amazon
Yellowbag - Save your favorite products and buy when the price drops
Billshark - Reduce your wireless and cable TV bills by 25% in 2 minutes
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
Price Tracker by Relbis Labs - Price Tracker is a command-line tool for monitoring the prices of productsFeaturesTracking prices and availability of products.Tracking Amazon Kindle books.Displaying products information in a terminal.Exporting data into Excel and YAML files.
Pricy - Amazon price watch