When you ask your question there are several variation which would change the price
In Pattaya about 750 baht short term or 1000 baht overnight and bar fine of 500 baht and a round or two of "drinks" maybe 500 baht.
In Bangkok more like 2500 s/t and 3500 overnight but it also depends on the girl and whether she's an employee or a freelancer.
If you go to Chiang Mai it might be cheaper.