I confess, I am posting about my own site, but I'll defend myself by pointing out that I am unlikely to profit from it, I'm just a SAHM trying to entertain myself!
If you consider this self-promoting (though I am not promoting my own book) please just tell me and I'll remove myself. I really just started writing the site because I wanted it, but thought it would be something worth sharing.
allows you to search for books you want (digital and print) and it will email you when your books become available at the price you want. Bibliosaur uses Google to authenticate, so no need to create any accounts. Also, because I'm not concerned about profits, I search Amazon, Barnes and Noble, Google Play and will be adding more. So this isn't just a kindle thing.
Anyways, I'd be interested in feedback. Please let me know what you think and what you'd like to see.
To people outside of the US: I've heard your complaints about being left out. If you have interest in this kind of site, let me know and I will add you to my list of updates.