I check the Deals, Freebies forum here on Mobileread. ATDrake posts a daily Amazon KDP pile with plenty of limited-time freebies in a mixture of genres. During the past month or so, I have accumulated over 700 titles. I am not sure of their quality, as I have not yet read any. I will probably end up deleting many of them in the future, but I am also sure that I will find some gems amongst the rough. Check out other posts in that forum too for freebies.
I believe this will be enough to feed your dual addiction
