CamelCamelCamel (Amazon Price Tracker)

Amazon changes prices 2.5 million times per day using algorithmic pricing. CamelCamelCamel tracks the entire price history of every Amazon product and sends you an alert when it drops to your target price. The browser extension (The Camelizer) shows price history directly on Amazon product pages — revealing that the "50% off" deal is actually the normal price, or that the item was $20 cheaper last month. The site tracks 18+ million products. Set alerts for big-ticket items (electronics, appliances) and wait for the inevitable algorithmic price drop. Black Friday "deals" are often higher than the lowest tracked price.