There’s plenty of options if you want to sus out a decent Z-lib mirror or get on tor to find the official deep web version.

The baseline kobos go pretty cheap too, or you could get a second hand kindle, jailbreak it - which is meant to be really easy, and install KOReader.

That’s the eBook app I use on my phone and it’s great. The interface is a bit intimidating at first, but it’s good once you get used to it