never buy a graphics card for cheap. they are pretty much overclocked.
your local dealer could support you with a case, if you dont have already one.
i bought 2 v2 xeon cpus for 50$ each a year ago.
now you should get v3 for that price on ebay.
then you build a computer arround it.
the mobo can also be worn, but should cost a bit more. maybe you have luck if you get a cheap xeon mobo used. asus is a good brand, but not if you want to go virtual.
i can sell you a xeon cpu with 4 cores for a friendship price of 30$
i bought a gtx 1050 ti , everyone told me this graphics card is shit, buy a 1080 ti.
but it is enough for star citizen and nearly all the games out there and is very cheap. (i discovered no game where it was too slow.)
okay, you want it cheap, but a great performance peak you get if you use ssd hds not normal ones.