I think 30K is reasonable.
I’m not sure what other reasonable way there is to manage gambling ads on facebook. Every man and his dog would be jumping in if it was cheap enough, and it really would become a case of how do you get your return on what you have paid for.
PPC is just too difficult to manage on the volume of submissions, easier to make it a nice high amount like 30K, cut out most of the market, and you will still get people paying that 30K for gambling ads.
I guess FB thinks that do we get 100 x $300 media buys, or just get 1 x $30K media buy, and have that 30K media keep renewing their buys because there is very little competition and are getting their return?