I got a few HP Elitedesk/Prodesk computers. One with an i5 9500T for ~200€, a couple with i5 6500t for about 100€ each (one small factor, the other a bit larger, with a PCI slot for a GPU). Not the most recent or powerful, but more than Enough for a homelab with a handful of VMs. Power consumption sits around 36-50w for the 3 machines, a small dlink switch and a Synology NAS with 4 drives.