It varies depending on your site, it can vary a lot, but you might get between $1 to $5 per thousand views.
If making your site ugly made you rich that would be one thing. If making your site ugly can pay for a Netflix membership that's another thing. That said, a site like that might cost $5 a month to run and it is possible it could cover your operating costs.
Currently, it's hard to justify working on anything new for it since it is just a helpful web-tool, there's really no future for it beyond making it slightly more helpful for people's niche use-case. On the other hand, I don't want to ruin it for a couple bucks a month, so I need to be really careful on how I do this.
(e.g. when I was at rock bottom in my life, my HELOC was maxxed out and I just rolled my car, I started what I expected to be a difficult job hunt so I created an 'application management system' and talking about that landed me a job at an AI company with my interview. Out of the experience writing that I've written a few intelligent assistants such as an RSS reader which shows me just the most interesting articles and an image sorter that lets me easily work with 800,000 images with Chinese metadata even though I don't really know Chinese.)