[BizarroLand]

I run it on my NAS computer in a ubuntu server vm. It was 20 minutes to set that up and another 5 to install and point my router's DNS to it. Maintenance is a monthly login, and a biannual update after puttying into the box.

If you want a one-purpose device for it, then you would be looking into buying a SOC computer like a Raspberry PI 3 (should be cheaper than the 4) and about an hour to set it up.

One little thing I have done is set my router's secondary DNS to 1.1.1.1, just in case the power fails or the PI goes down. When I set mine up I completely forgot to set ESXI to auto-power on the VM, so after a brief power outage I had no internet for almost an hour because I had no redundant DNS configured. I got blindsided by my own mistake. Now everything is on a UPS and the VMs are correctly configured in case power is lost long enough to require a shutdown.

https://pi-hole.net/ has more info on the install.