Back in the mid-2000's, when I was restoring Midlife, I was searching for both a driver and passenger side doors in very good condition: good interior grain, no rust at the bottom, and no major dings on the exterior sheet metal. I went to AZ, bought what I thought was a good door off of a recent wreck, and it turned out to be full of putty. Bought two doors at major shows in Pensacola, FL, and both were junk. During this time, folks from SoCal were saying they were a dime-a-dozen at local swap meets for $100 or less (yeah, right). Bought two more doors via e-mail leads, and both turned out to be unrestorable. Finally, I got a lead from an Internet denizen in Oregon, close to my in-laws. Flew out, and examined the door. It had been stored in an attic since 1968, and was only $80. I bought it quicker than you can say "sold". Just down the road was a small Mustang parts outlet (both used and new), and found a stripped door for $110. Bought it, and took both to my in-laws for boxing up and shipment back home in used bicycle boxes.
The days of finding good used doors quickly and/or cheaply is long gone, my friends. I spent 3.5 years and bought 7 doors before I found 2 good ones. If you run across some, even if you're not needing them, buy them up, as they are only going to appreciate in value. I'd easily pay $250 for a good quality door.