Is there any demand for proof reading service here?

I'm not a native writer or proof editor. But yesterday I struck deal with someone who is for my website! But i do not have enough work as my content production limited to 10k per month. This is kinda super expert proof reader. I'm wondering is there any demand for proof reading service here and what should be the pricing and TAT

Not too sure. People here generally write their own content, either because they believe it is good enough or they can't afford to pay somebody, or they pay a pro writer to write their content which the pro writer doesn't need a proof reader as such. Maybe work as a VA, and a writer could pick you up that may want you to occasionally proof read? Not sure.

From my experience as a seller: Probably not. For pricing you pretty much have to charge $5 per hour or less to get any interest from members here.

Clients likely wouldn't be coming from BlackHatWorld members, but BlackHatWorld ranks very high in Google and if you make a good sales thread, you can attract possibly big clients outside of BlackHatWorld.

That's your only chance, that I can see. Either a big service provider here hires you or an external company finds your thread from Google and hires you.

So you would just do keyword research on proof-reading keywords, stuff it good, and let it sit without much attention. It isn't a big investment to upgrade your account and open a sales thread, but don't expect members messaging you every day. Expect maybe 1 person a week messaging you, and 1 person a month actually buying. But you are looking for that 1 big sweet client.