Just returned from Hatyai. I'm giving my 2 sen info.
There're mainly 3 areas you can find girls. I went to a couple of those. I stayed in See Kim Yong (SKY). 5 hotels there that I noticed, DaiIchi, Garden Home, Merlin, Hatyai Asia and Hatyai Palace. Reasonable rate with the most expensive at 700B and the cheapest at 490B. Farms, normally named something karaoke, are within a shout. The boss I talked to at one of those said there're 7 karaokes, most on Chaiyakul Uthit soi 3. These are open from early morning. There're a few true karaoke bar but only open from 6pm. You can take motorbike and get them to drop you off at 7-11, then start walking around within a distance of 50m. Fare is only 20B from most places. I noticed the girls are also paying same fare so not worth to argue about.
I did went there at 8am and the chicken haven't come home to roost yet. So, the boss there told me to go to Channivate. So, off I went to Channivate 2. A number of joints there. if you can't find anything, try Channivate 3. All within walking distance. The 3rd area is ThongSao but they said mostly has illegal Myanmar girls.
Generally, the damage is 1300-1500B whole day for those who already given birth or not so attractive. For baby-less girls and attractive ones, the standard is 2000B. Fresher girls may cost 2500B. Some are negotiable. The last nite I was there, the boss offered me 1500B for this baby-less girl. She's damned pissed off with her boss. Her share is only 800B instead of 1100B.