We recommend buying Thai swords directly from blacksmiths in Ayutthaya. Often these are small family businesses that have literally several hundred years of experience in the production of such swords and thus contribute to cultural preservation.
We usually craft our wooden training swords ourselves. For this we use simple and inexpensive materials that are available in every hardware store. You can find our video tutorial here.
We purchase our steel swords from Kai Meed Ayutthaya.