I recently bought one of these: https://www.intel.com/content/www/us/en/products/boards-kits/nuc/kits/nuc6cayh.html https://www.intel.com/content/www/us/en/prod

I recently bought one of these: https://www.intel.com/content/www/us/en/products/boards-kits/nuc/kits/nuc6cayh.html https://www.intel.com/content/www/us/en/products/boards-kits... and added 4GB RAM and a 120GB SSD for about US$230. It runs as a TimeMachine backup server. It's reasonably fast and very quiet. In the end, it really depends on what you want to do with it. [Edit: If you want to go really cheap, get a Raspberry Pi.]