the baht is about 1usd/30tb
fartex is the most famous camp, expensive, in the middle of nowhere(outside bangkok) there are decent camps in phuket, more to do, beach diving etc.
Lanna and others in chiang mai might be a good option, you can try out which camp you like in a smaller city close to the mountains, but not the coast, the owner of lanna is a good guy
koh samui has the wmc camp, Paul Slowinski fought out of there, I could have fought him, but got injured while training in thailand(he would have won most likely)
you will get better training at all the camps if you make it clear you will fight for the camp while in thailand, their are many events and they like to see farang fight, if you are not intending to fight, the attention and training you get can vary and be very basic
maybe plan to travel and try various camps, buses and planes are cheap as are hotels, you will usually get a better deal if you get your pad when you arrive, if you book something on the net you will pay twice as much, go with friends, get a house it will be crazy cheap by the month, great food and medical care, super friendly people outside of bangkok, prostitutes calling after you in tourist areas $25 dollars all night, usually need to give her a ride home, make sure it's not a "lady-boy"