Go to an ACE hardware. They have everything there for under $10 to build one. Go to the PVC pipe section. Youll see black rubber hoses about 6 inches long with 2 clamps on them, buy one that looks to be the right size (there arent too many different sizes, youll know which one is right) and buy a pvc cap that fits inside it. Then ask someone there where there valve stems are, they only have one kind, a brass type that will screw in. Drill the cap out and screw the valve in and clamp the cap into the hose. DONE.