Adam, check at a good auto parts store. Really, you do not need to paint the inside of your barbeque pit since the grease, soot, smoke and other chemicals from the cooking process will make it almost rustproof anyway. No paint will stand up to too much heat but the grease and soot will. Be sure to "fire up" your grill a couple of times if you used something like 55 gallon drums to make it. Those fires will burn off a lot of nastiness before you actually use it for cooking.