me and my cousin made one for 35$. 2$ -- 4' long piece of 2" PVC pipe for Barrel 2$ -- 2' long piece of 4" PVC pipe for Chamber 5$ -- PVC primer and cement set 2$ -- 4" to 2" PVC converter 12$ -- 2" ball valve (big splurge) 2$ -- 4" cap 5$ -- air compressor fitting, and bushing 5$ -- 50 lb bag of po...