Hi , from some view points that consider cost vs performance relative to resource usage - these systems might be somewhat over-spec'ed  as your usage requirements seem to be quite low resource

An 8 core cpu for streaming youtube ?

My opinion is to also consider total cost of ownership by including support programs such as internet security suites and office etc and hardware devices such as an external drive for backups - and I would suggest that is better value to purchase fully functional / supported utility and application software rather than using freeware

That having merit maybe consider a new computer in the $400 range and $200 for support software and direct support devices

However there are often other factors in a selection and as such i would suggest , considering your resource requirements , the system with the best warranty conditions

(need to add os license cost as well)