Solar hot water heater is made from an old keg that I got from the rubbish tip for $5 and the pannel cost two dollars.All up with plumbing it was about $50.The keg is insulated with old carpet.Another way would be to put the keg into an old fridge with a glass sheet instead of the door.Paint the keg black and put alimiumn foil on the inside of the fridge, paint the outside of the fridge black, face it to the sun and wolla batch solar heater..cheers Stewart