I’ve never self hosted, started maybe two years ago. First I’ve started with a Raspberry Pi 3, but quickly decided that 1GB of ram, and limited power was not enough for my needs. I’ve got myself a Dell OptiPlex SFF (used), it came with 16GBs of ram, then I’ve added a 4TB HDD. I’d say, this is an “entry” piece of hardware, as it’s cheap and sips power (around 15-20W at idle). If you don’t need the disk space or much power, go with a micro (whichever manufacturer you chose, HP, Dell, IBM), they’re cute little boxes that make a RasPi seem both underpowered and overpriced (for a used one anyway).