If you want a Zimaboard system with 8GB of RAM, you’re looking at 200 bucks. You have to get the mid-range one just to get 4 cores.
I bought a used 2012 quad core Mac mini which also has 2 SATA slots for about half that price. It idles at 13W according to Apple, and the person who sold it to me already had it upgraded to 16GB of RAM.
This is a machine with the “Apple tax,” i.e., a higher resale value than a PC.
You can jump on eBay and have a blast with “HP EliteDesk” as your search term.
I have to admit, though, a PCIe slot on a system this small is nice to have.