Just poke around eBay for old think center minis. Try to get one with no hardrive and minimal ram because you'll be upgrading those anyways. You can snag them for $60-$100 usually, with the power supply. 32 gb ram is about $40 and 4tb ssd is about $200. But you can go 2tb of course if you wanna save $100 or so. 4 isn't needed for anything, just a little future proof.