I see certain cars priced fairly but i think its cars no one thinks of, 68-9 Galaxie/ Torino with 351 windsor, Ford falcons any year, 4 door anything usually Buicks and olds can be had for 5 grand ish...OR there are the cars someone else started and arent going to finish but those are pricey and you may end up with a rolling shell and a bunch of parts, youll have to know what goes where and whats missing...any "big boat car" from the late 60s..,noone wants em the 455 Pontiac Catalina afro example...I see them around in good shape 4 door sometimes two door but two door brings in a bit more money. But you are correct even Fox body mustangs are through the roof...
here's one like I'm talking about on CL in my area:
1969 Pontiac Bonneville - cars & trucks - by owner - vehicle...
not something people want but under 5 grand and looks fairly complete and decent. I suspect some guys are shipping US cars overseas too one day theyll all be gone...