I mainly specialise in laptops these days, but I do have a few part exchanged towers with fresh windows 10 installed with Office and SSD, wireless adaptor at £75 each (monitors, keyboards mice optional extra)

Windows 10 still has some life left for those on a budget

although updates will no longer be available, unless you enrol in extended support to have one extra year of updates, Microsoft have had 10 years to perfect any vulnerabilities

provided you are using a 3rd party anti virus live Avast or Avg and google chrome, you should get another 3 years out of windows 10