@Col****
^what
@Da**
said ;) You can extend a 30 day visa exempt entry ONCE for 30 days for 1900baht at the immigration office
When that runs out you're done and you either border bounce (go to a border, stamp out of thailand, stamp in&out of another country and back into thailand) to get a new 30 day visa exempt entry
OR
You go to a thai consulate in a neighboring country and BUY a tourist visa for thailand.