Im all loaded up with every vaccine you can imagine from past trips, but my buddy just got his for our trip coming up to Thailand, and I think he had to pay ~$200 for everything he needed. I would just print out the CDC recommended for thailand and take it to your doctor. Depending on the doctor they are they will tell you need everyone of them, or say you got to only worry about a few.
If you are current on all your standard shots (hep, MMR, etc etc) you might get out pretty cheap. I would look into student health (if your in college,) or city clinics if you are trying to save money. they might be cheaper there.