All of Cory Doctorow books are DRM free.
https://shop.craphound.com/
I added a link, thanks! Mr. Doctorow seems to include 3 formats in every purchase (PDF, MOBI, and EPUB), which should cover just about any device.
alt Hacker News
I added a link, thanks! Mr. Doctorow seems to include 3 formats in every purchase (PDF, MOBI, and EPUB), which should cover just about any device.