I use a 2008 Dell Inspiron laptop as an office PC. I upgraded the CPU, which would be absurd for a new notebook. I also upgraded to 4 GB DDR2, and an SSD. It still works great!
I think it’s always best to keep things maintained and continue using them instead of buying new things. Maybe some of us have a bunch of old stuff laying around. But what stuff are you still using?
PowerEdge R720 built probably around 2013 still kicks ass. Of course, I only bought it a few years back, so “it’s new to me”. But the hardware is quite old.
A new PowerEdge would probably be in around $15k + .