I've often resorted to using elastic bands! If you ask your postman nicely, he'll always have hundreds to spare!
You could also cut up an old bicycle inner tube, measure off half an inch and use that...
How about a large black jubilee clip, painted the colour of the belt, or better still, buy some of those little coloured ones for contrast!
Actually, a short length of chain looks pretty alluring, especially if it's gold or silver! The welding kit is always available on Ebay, but I'd just tie the chain in a loop or a bow, and have a couple of dangly bits! Very sexy!!