This is probably different for different cities & cultures but where I live there are a lot of small book shops. Both for second hand and newly printed. People also tend to leave a lot of books on the street to take. I recently found Dark City, Silence of the Lambs and The Dean(?) in his domain on the street. All in good condition and I enjoyed eating them.

I really don't understand why everything needs to be tracked.

Reading for me is a journey for its sake, the destination is not interesting.