Hi Lens,
I use cheap Chinese clamps that are about $10.00 for 4.
The key here is how much would you pay for a torch holder $20 to $50. How much is the miller torch holder ?
The one I made cost $5.00 for the clamp and say $1.00 for the 6mm or 1/4" round bar. All up $6.00 plus 30 minutes of my time. It would take that long to drive to the welding accessory shop so lets just say it cost $6.00, pretty cheap and a cool little project.