I just bought a used Lenovo ThinkCentre M710Q Mini Tiny Desktop PC Computer i5 6400T 1TB SSD Win 10 Pro from Ebay for $289 AUD and plugged in some oldish external SSDs and HDDs and now have 10TB of storage. I’m really pleased with it, it took about half an hour to install Proxmox and I’ve now got 5 VMs up and running.