I work as a computer repair technician and my workplace has some really old cheap (90$) server hardware for sale. They have 32gb of DDR3 and old dual xeon 5606. I would probably upgrade them because old xeons are dirt cheap. They also have some old workstations too that could be suitable for hosting, similar amounts of ram but new processors.
Not energy efficient but that’s fine since they would literally be a space heater, and if maxed out those old CPUs can still get some work done.