Here is a great site for used books .Not sure if you know about this .
https://www.thriftbooks.com/

I have bought books on the website.
I add this. I didn`t have a favorite book or type
However My family and extended family did the following
They made Books Fun and it was adventure. Books introduce me to thoughts and ideas. I read as a kid. I read Call of Wild,Ben Hur,a Christmas Carol.
Robin Hood.I also had some "coffee table" type books as
well. My problem is I don`t read anywhere near like I
use to as a kid. For me reading was introduce as fun
something to do.