My old mig cart was made from bed frames cut up and welded together. Yes, it was cheaper. It also left much to be desired.
This past weekend, I bought one of these:
Craftsman 2 Tray Service Cart
They were on sale for $40. I would watch Sears for the price to drop again.
After I put it together, I had a thought: Why not cut a hold in the top tray for the air tank? So, I did. I cut a hose and used that for the edge of the hole.
Nice, easy, cheap welding cart. If I had to do it again, I would've put the hole on the other side. I'll just switch the handle one of these days
I picked up another, since the stick welder will fit on the bottom shelf. I just have to put it together around the welder.