I totally understand that you can't offer a $1,000 bounty, you aren't Google or Facebook.
Would it be possible, however, to take donations (cryptocurrencies?) that can be used specifically for the bounties? I'd put in 50k DOGE towards that, and I'm sure others would too.
I appreciate the kind gesture, but I really hate accepting donations, and to that end we haven't accepted any in ~8.5 years.
> wants people to pay for contributing to the site
The reason you feel against donations is because you probably have a negative psychological view of accepting help. You probably feel that you bother people when you want to ask them for free help in real life.
Well this mental block you have is not true to the world. You should do what other good entrepreneurs do and stop putting your own limiting beliefs onto your non-profit business.