I am guessing this to be 15 years old, maybe more. Still works fine. I bought a replacement a few years ago thinking this one wouldn't last forever but finally I just started using the new one because it had been sitting in the box so long!

$15?  

If it doesn't sell here I plan to have it at the Winnipeg swap meet this coming weekend with a $20 price tag on it.

To give you an idea how little it's been used, the tank on my mig welder has about 1/4 left in it and was last filled around 2006...