BookBub is like Groupon for ebooks. Every day you get an email with a new discounted book. They do a pretty good job of selecting interesting books, but that's just my taste, I'm not sure if everyone feels that way (although you get a choose a category that you like). The biggest downside is you get a bunch of emails and ebooks are already so cheap or free. There are literally over 40,000 free Kindle books available so I might spend some time reading those or checking them out on my Amazon prime free check-out library.