Boxing shorts

Where do I find Muay Thai boxing shorts. I have been asked by a friend to get him a pare but where to buy them? I went o Bo Bay a found some in a shop but terrible poor quality and when the shopowner saw me he said the cost 390 THB!! 39 baht would probably be the correct price for his ****. Should there not be a proper sporting goods shop for Muay Thai stuff here in Udon?

Super Sport at the Central Plaza Mall.