best/ cheapest i could build as per your needs slightly higher than your price range.. keep scouring kijiji for a deal.. maybe post links here so we can give input on them?

intel: http://ca.pcpartpicker.com/p/qq3GK8 , Total: $769.82 (without O/S)
AMD:http://ca.pcpartpicker.com/p/bq3GK8 , Total: $663.37 (without O/S)

This post was edited by Canadian_Born on Feb 3 2016 05:34pm

u can send what you find to me and i'll give u a honest opinion.
Personally though you should just custom build.
pay someone local 50$ to assemble if u have to.

Dont buy intel chip
Get an amd chip, much cheaper and equally effective
Pm me, i can help you with a list less than 600$ easy
You might want 16gb ram with all the multi tasking

This post was edited by Odell on Feb 4 2016 12:28am

Also you dont want to buy a used computer really
Parts might be stripped or perhaps a defective part etc
Sometimes buying cheap can be expensive... If that makes sense

This post was edited by Odell on Feb 4 2016 12:37am