i used a length of copper pipe from the zircon suppliers and wrapped it around a keg. Only problem is that it was 10mm copper tubing and I am finding it hard to find compression fittings for it
The big green shed has 3mtr x 12mm copper roles for around $15 . I used 9mtrs with a few joiners and elbows and total cost was around $50 . So if you have some ability to create stuff , this would be an easy project and a big cost saving if you don't charge for labour .