I agree @Pdoggg. Standard bf in Bangkok for big 3 lb bars is now 500THB. And for ST going rate is 2K. But ofcourse one can negotiate and if a girl really wants to, she will probably agree on 1.5K. Personally I rarely discuss price upfront. When girl meets expectations I pay her 2K+some taxi fare (100). If she's exceeds expectations I'm happy to pay 2.5K+  I was in PTY few days before xmas, unfortunately didn't meet anyone worth of barfining hehe.