I been looking at this one:

https://www.amazon.com/Qotom-Q555G6-S05-Qotom-Industrial-Barebone-Computer/dp/B07KM7YY4Y/ref=sr_1_3?dchild=1&keywords=protectli&qid=1589660673&refinements=p_n_feature_four_browse-bin%3A2289793011&rnid=676578011&s=electronics&sr=1-3

$300 and it comes with a i5 7200U i could add 16gb of ram and add small SSD and be around $400...

I could also get a Lenovo ThinkCentre M92p, i7-3770, 16GB RAM, 480GB SSD $280 + a network card and outperform it. But space/noise/etc etc