Does anyone here use an older apple computer?    
I do some work for a small office.  They would like one or two of their workstations to be Macs.  Mainly they are just launching a browser and working in Google Docs.   Sometimes an office application, but I have them all using LibreOffice and they seem happy with that.
My question:  what would be the earliest version that is still usable?   I have seen a few MacMini's on eBay that are running HighSierra.