After pi’s got expensive I started picking up refurbished Dell micros and Lenovo tinys cheap and haven’t looked back. They are also perfect for the 10” mini rack[0].
Same. I have two Dell SFF 3070s and some MSI micro units in a rack - planning on getting some more for my Proxmox cluster. ServeTheHome has a great resource for the compute nodes [0] and GeekPi makes some awesome 10" racks [1]
[0] https://www.servethehome.com/introducing-project-tinyminimic...
[1] https://www.amazon.com/GeeekPi-Cabinet-Equipment-RackMate-Ra...
Shoutouts as well for the USFF HP Elitedesk and Prodesks. They are amazing. I even got one with a Ryzen CPU that had a dedicated GPU option - that GPU part was on eBay brand new for $60 and replaced the hard drive bracket. Not on par with a desktop GPU but way better than integrated graphics, for things like Minecraft in my case. I use a second one, this one Intel with 32GB of RAM, as my home server. (Jellyfin, Home Assistant, Tailscale, miscellaneous stuff).
What's cheap? Over here they easily run $300-$500 for thinkcentres and dell micros unless they're intel 4th gen with DDR3 8GB.