I'm probably the least qualified to answer your question because I haven't paid for sex in years - but from what I understand from those who do the going rate of 1,500 THB for a short time in Pattaya hasn't changed in decades.
I imagine you could bargain your way down to 1,000 with some of the PTY boys - but if they're charging 3,000 in BKK - isn't half price good enough???
Bangkok always was too commercial for my taste - geared almost exclusively for short-time tourists who may not have enough time to travel to other destinations, or they're simply ignorant of the actual cost of things in the Magic Kingdom which is understandable.