Can you recommend a website for ebook price tracking?

I rely heavily on Camelcamelcamel.com, however the site doesn't offer ebook tracking. Ebook items appear "out of stock" in the system which means the tracker won't generate notices / tweets / emails / etc. on a price change.

Anyone know of a website that will allow a user to track the price of ebooks? Preferably one that doesn't require a social media login...