You're talking about LDPE tubing (low density polyethylene). We (Buckeye Field Supply) carry 3 colors of tubing and all the fittings you'd need.
Our fittings are more inexpensive than the hardware stores I've seen - but if you just need a couple the expense of shipping wouldn't be worth it.
If you get translucent icemaker tubing from the hardware store, keep an eye one it to make sure you don't start getting algae in the tube.
Make sure you use teflon tape on the fitting threads.