I have vented over this often. I have scored some awesome deals on craigslist and some I've wondered WTH happened? I guess more often than not it's worked out well. I have discussed several times in the past how on Craigslist if it's listed with an Email only they will never respond. The only time I had a response was when I bought 2 welders and a shrinker/stretcher last fall. The guy outright lied, it was pretty obvious when I was asking about the machines but I was still pretty sure I could come out. I was able to repair both for less than $150 bucks. The machines are probably worth $1500 a piece.
I have done well on Facebook market place. I rarely ever see any Plymouth parts our era there but I have seen several cars for sale at reasonable deals. Bought lots of AMC Jeep parts there. Vintage tools and machinery galore!