If you just need a tiny, fanless board that runs linux, like-new Wyse3040 can be had in any quantity you like for ~$30 - $40 (ethernet only, though). Wyse5010 is a bit bigger and more capable (and has built-in wifi) around the same price.
https://www.ebay.com/sch/i.html?_nkw=wyse+3040
Many listings will not include the power supply, but if you have a drawer full of wall warts, you can probably find something that works.