I agree, that's what I'm rocking: a bunch of 8gig pi's doing everything from RAM, and a threadripper DB server. All at home, all for <3k out front. Equivalent monthly bill at a major hoster would be >200/month more than electricity + the cost of <low single digit> hours needed.

The same setup with a more reasonably priced consumer proc (but no ECC) would be around 1.5k out front.