I have never been to S Korea and Japanese and therefore have no knowledge on the prevailing market price;
As for the PRCs working in the massage establishment in Malaysia, the price is about 230 ringgit; about HK$1000 for a full course; was told that they are young; the same one in Bangkok will cost about the same (about 5000 Baht)
For those hanging around Shenzhen, it's like playing mahjong;
1-4-7
2-5-8
3-6-9
(sit. short time, overnight)
For those at Zhuhai, it's 200 for short time and 5 times for overnight
For those working at the border, it is difficult for them to get travelling documents to visit HK.
If you don't mind the rejects in Bangkok, they cost 500-1000 Baht and English will probably addressed them as Elder Sisters
These can be found in Chinatown catering to the old people's club
As for the Thai girls; was told that those above 25 are treated as rejects and hence have to move overseas to continue the trade; There is a message establishment in Bangkok that I know that offers 15-16, but these are not Thais.