Here's examples of idle power consumption of second hand mini-pc's i've tested, running Ubuntu, measured from the wall:
Dell Wyse 5070 with Pentium Silver J5005 ~ 5W
Fujitsu Futro S940 with J5005 as well ~ 7W
Dell Optiplex 3080 Micro with i5-10500t ~ 12W with two SSD's
In comparison, my Ryzen 7 server build consumes about 22W idle (before I added GPU), has 4x SSD and 4x RAM sticks. I like raspberry pi, but for most purposes an used mini-pc is a better choice.
Dell Wyse 5070 with Pentium Silver J5005 ~ 5W
Fujitsu Futro S940 with J5005 as well ~ 7W
Dell Optiplex 3080 Micro with i5-10500t ~ 12W with two SSD's
In comparison, my Ryzen 7 server build consumes about 22W idle (before I added GPU), has 4x SSD and 4x RAM sticks. I like raspberry pi, but for most purposes an used mini-pc is a better choice.