You could consider an Intel-based mini PC. There are several Chinese manufacturers offering Celeron or i3 -based systems on the cheap.
While not as power sipping as ARM boxes, their consumption might be acceptably low to make them an option for 24/7 operation, providing services to other devices on the network, such as media streaming, file serving, ad filtering, and so on.
During Prime Day some of these were discounted well under 200 Euros, for a little more you could also have brought home something that could double as a desktop PC in a pinch (e.g. with 8 GB RAM; I would actively advise against 2 GB if you intend to run Windows or one of the heavier Linux desktops).
Alternatively, if 24/7 operation/power consumption are not critical, space is not an issue, you could shop for bundles of old components on eBay.
Generally there is an age cut-off, systems that are still more or less viable gaming-wise (e.g. parts that can be paired with a recent or contemporary video card and still produce acceptable performance) obviously tend to cost more, but then price drops rather sharply.
If you have a full-fledged media PC, then you could keep whatever parts are still good from your old build (e.g. case or SSD) and replace the rest with a second-hand bundle, supplementing with new parts if needed, say you need a PSU for instance.