I picked your parts to start cheap.
Expected 168Mh/s after Biosmod @ 850 Watts
You will need these 6 GPU's for your cheap rig.
You will need 6 GPU risers for your rig.
An SSD will be better for miners.
Miner powerusage is between 800-1050 Watts
A 6 GPU Motherboard
The cheapest fast LGA1150/1151.
4GB is enough, 2 at once is cheapest.
A power button to turn it on!
You should always make your own!
The current Cheapest Components for your Rig.