China has reciprocal diplomacy for the visas, so it'll charge the same as your country.
The US one just went up to 1100HKD when i tried to get it, but they denied me twice, keep in mind I've had multi-entry visas for the last 5 years, US citizen.
First time they won't give me 1 yr because they said my HK visa expires in less than a year, so I could only get it after I renew my HK visa.
Ok fine, after that I went back and one of my old china visas fell out due to the crappy chinese glue they use. Another one is peeling off right now. So they won't give me a visa unless I get a new passport.
I was just amused about the whole situation and figured I won't go to China and spend my money elsewhere. I'll just get a visa back in NY when I return, they're pretty lax and give you 90 days entry and don't require any HKIDs or things like that. The chinese consulate ppl in HK are miserable agents who will look for any reason to deny you and only give 30 days entry.