I get most of my stuff at the junkyard, with some of it coming from Ebay or Year One. It all depends on what you want and what you have to pay. For sheetmetal, the junkyard stuff is really better than reproduction, unless you can't find a rust free panel. Factory used parts fit better. Chinese made imitations rust faster and fit poorly. It all depends on where you live too. Down south, where I live, panels still exist with relatively no damage for low prices. Up North where they salt the roads, they are getting rare.
The sad thing about the steel prices is that all of the scrap is going to China and India to support their industries. They are literally stripping us bare, closing our factories and buying the equipment, etc. Thanks Clinton and the Bushes for ruining our manufacturing base!