I am a big fan of "mini desktop" computers for this sort of task (my lemmy instance is running on one). You can usually pick them up used/refurbished for pretty cheap with decent specs: i5 or better processors, upgradeable RAM (SO-DIMM), M.2 or 2.5in SSD. They are quite small, and relatively low power. I have a few in my homelab, and one acting as my media-center PC in my living room.
