The Serve The Home articles inspired me to go this route. I want to improve my understanding of Kubernetes for work. I picked up an HP EliteDesk 705 G4 mini desktop and an HP EliteDesk 800 G4 mini desktop. Each was less than $200, and included 16 GB RAM, 256 GB SSD, HDMI and DP outputs, and a power brick. One from Amazon ("renewed") and one from eBay. My 705 came with a Ryzen 2400G, and the 800 came with a i5-8500. I'm not planning to stack them so I was happy with the 65W chips although it means keeping the top of the case clear for cooling. Serve The Home recommends the 35W chips if you are going to stack them.