I scored an Optiplex 7050 SFF with 250GB SSD, 16GB RAM, and an i5-6500 for under $100 on an ebay auction last year. I threw in another 16 GB of RAM, an i7-7700, 300W PSU from an Optiplex XE3 (factory for a 7050 SFF is 180W…), factory SD card reader + faceplate, and an Nvidia Quadro K1200 (why? I don’t remember, but it’s better than the iGPU).

I had the same IP address for almost four years through Spectrum in Upstate NY, on a residential plan. It changed once. I ended up moving anyway though, so I didn’t get to see how long that one stuck around.