Any suggestions for a reasonably priced hospital for a work permit medical certificate. Thanks! 

Ask the teachers....it is quite common for a small practice to do this for 50-100 THB.  Maybe just walk in to a few licenced physician offices..they will all have the almighty stamp.  I got one in Washington DC, and zero diagnostic tests were performed, and no real proof of vaccinations was produced, but that was 55 USD, a good deal there, but since I have heard of many getting it very cheap here.  Avoid the hospitals....