Thank you, glad it looks good for you. Yes using Google search API. Yes paying out of my own pocket right now. If you know anyone at Google that could lower the price that would be great :) Ya, not break even right now...
I'm actually in the same boat with goosh.org (also paying for it myself).
I think bing results might be cheaper at scale because I see a bunch of bigger services using it (like duckduckgo, but they will have a special deal for sure).
If I remember correctly there is also a hard limit for google results (10k/day?), so it doesn't scale even if you can refinance it somehow.