Our expert writing service (2020)

This is basically "Get a native-level English speaker to skim your document and flag/fix problems" as a service, and critically, it's inexpensive enough to be realistic for individuals.

Reaching native-level skill in a language is incredibly difficult – much harder than becoming fluent. For non-native speakers who need to publish professionally in English, this is a powerful service.

(I'm not affiliated with Grammarly and I haven't tried this service. If you've tried it, how'd it go?)