Smashwords comes to mind: https://www.smashwords.com/ https://www.smashwords.com/ . Once you buy a book, you get a DRM-free epub that you can open in whichever

Smashwords comes to mind: https://www.smashwords.com/ https://www.smashwords.com/ . Once you buy a book, you get a DRM-free epub that you can open in whichever e-book reader you fancy. There are in fact more of such stores, but this is the one that I use and remember.