A very rough canvas that is used by many artists can be bought at either Liberty store or Simon Quan in Belize City. Most if not all of the art supplies I've seen in stores in Belize has been student grade and not good quality at all. I've seen artists use regular latex house paint or chinalak for lack of anyting else. I have had the best success with purchasing supplies online on websites like dickblick.com and having it delivered to someone coming down.