I think this is probably in the wrong place - hopefully, a mod will move it accordingly.
Adds price history charts and the option to be alerted on price drops to all Amazon sites.Price History charts
Price History charts for over 200 million Amazon products, even for different versions, colors or sizes of a product.
This is a free Chrome extension - it automatically adds a chart to an Amazon product page, allowing you to see how the price has changed over a period of time. It's basically CamelCamelCamel, but has all the data added to the Amazon product page, so you don't need an additional tab open.
Anyway, I find it very useful, thought I would share.