but that one is 500 with no RAM at all, which is quite hefty.
I got mine open box off from eBay. You could search in a similar way. I hunted for a few days, with terms like "NAS", "N100", "N150", "MiniPC", "4 Bay", etc.
though I’m not quite sure what to pick best, motherboard being the hardest one.
I'm not sure on this, so take it with a grain of salt, but I think non-NAS oriented mothebaords aren't optimized for low energy consumption, specially on idle.
Best of luck!
https://www.tobyord.com/writing/hourly-costs-for-ai-agents. This person analyzed a question very similar to yours. For me, this means:
I don't really know what to make out of that in a broader picture