Estate sales are still very effective means to acquire multiple machines, especially if they have been sitting in storage for years.
It does not matter if they are SS or EM.
Often times owners do not even really know what they have for sale.
If machines do not work, many people will not buy them.
If machines "sort of" work, more people think they are worth a small fortune.

The latest example I can remember was about 4 months ago, when 3X 4MBC were purchased for $550, all unworking, mostly complete, and in general good condition overall

I am not saying for anyone to sabotage a game on site like cutting a power cord (which I have actually observed with my MKII eyeballs and pointed out to the auctioneer who physically threw the person out on his a$$), just be mindful of the difference and be prepared to 'pinjockey', if the sale is in close proximity to a major urban area or city, or advertised in multiple ways.

"A long time collector is like a 'big game hunter'. Patient, methodical, and always ready."