Hey, thank you! Not to discourage you or anything but monetizing with affiliate book sales is a loong long way to replace a full time job. This post got to the HN front page (first time for me) and I'd be happy to make $15-30 today.. and this is the best day with thousands of visits. I started and continue working on this because it's a passion. I love books and I love seeing people buy books because of something I made. Good luck!
Once your site gets traction it should be easy to get sponsored listings which should add at least $2K to $4K per month depending on who is interested. Also not sure if you're already doing it but try to build an email list. That's where the real money is imo.
The thing about your email list is that you people who are voluntary subscribing to you have started to trust you a little and you know what they like.
Now it's time to give them more value in terms of content, bonuses and other things which they are looking for to create loyality. After that you promote an existing product as affiliate (in your case it could be blinkist like site) or better create a product that is aligned with the interests of your list.
Sorry I'm on a mobile so it's hard typing but here is a case study for you(1). There was another one from nomadlist you should lookup too.
I am also looking at monetising via affiliates - is it a viable approach? Would you say that you could replace your full time job (if you have one)?
Congratulations again.