Around here I've seen them listed for as little as $200 and as high as (cough/giggle/smackmyhead) $550.
One CL ad reads for one listed at $450 starts out : "unit doesn't run, but..."
Well, sir, every smart buyer WILL run at that price. Run away.
Thanks, everyone, for the advice. I guess I assumed that any wire made in the 40s or 50s would have to be replaced for safety's sake, but some of you say it isn't so. Good to know. And yes, I would NEVER check a wire with it plugged in.
Well, never AGAIN, I should say!