Depends on which problem your tackling. With App reviews for example it is very easy to rate limit the 100 USD developer licenses. And also in cases like the one the medium article is facing businesses would gladly pay a hundred bucks to get real humans to produce competent answers/reviews/decisions. And if you dislike this solution because it creates a google tax (pay us or we'll block your site), make it not a service payment, but a security deposit which they'll only keep if you are fraudulent in some way.
