The thrift shops around here have stuff get snapped up pretty rapidly... There are several I will hit, but hasn't been great lately - Got lucky at a hock shop the other day, scored a Nikon D300S that appears to work fine, along with a 24-70 2.8 Nikon lens, also appears fine, which sells for $1600 new, for a total of $160. Their guns were overpriced, of course.
With the cast iron, I'm going to be sanding the inside bottom, probably to about 3,000 grit (not that I'll see much after about 1200 or so, but hey...). Then when you have the mirror finish, couple of rounds of seasoning, good to go.