Used “1-liter” business PCs which come with a modest amount of RAM+storage (assuming you’re likely to replace/upgrade after buying anyway) and an 8th gen Intel CPU should run between ehhh like $125 to $250 depending on which model CPU, how much RAM etc. Totally worth it IMO, I use one with an i5-8500T as a Proxmox host for my web services and so far I’m quite happy with it. Snagged a deal on it a couple months ago, $110, shipped with 8GB RAM and a 256GB SSD which I immediately replaced.