One good thing about the Kobo store is that they make it very easy to tell what sort of DRM an individual book is using. Anything marked "Download options: EPUB2 (DRM-Free)" will allow you to save the epub file on your PC and copy it to any device that uses epubs.
Lately I've been trying to see just how much DRM-free material I can find on the Kobo store (and elsewhere). There's quite a lot out there, actually. I've been recording the results in this thread:
https://www.mobileread.com/forums/sho...d.php?t=257084