Something small and 2 or 4 GB RAM. Raspberry pi’s compute power is good enough for me, I’m not doing anything too intensive.
Is raspberry pi 4 still the best answer?
I am a tinkerer and don’t mind tinkering. I typically use Gentoo Linux as main OS. I also don’t mind ARM or other architectures. I’ve been eyeing the RockPro64 as well.
Look up 1L mini PCs - Dell, Lenovo, and HP have similar one liter mini PCs that would’ve been used as a lightweight frontend in offices. They are easy to find on eBay and can be pretty cheap.
For example, my lab at home consists of three Lenovo Thinkcentre tiny machines. I bought them off eBay for $60-80 USD. They each came with a 500gb HDD and 8gb RAM. I have since upgraded them all to a 500gb NVME, 500gb SSD (they have a 2.5" drive bay), and 32gb of RAM. They run as a Proxmox VE cluster.
I think I might have $500 USD into the entire setup, including my 10" wide rack enclosure.