Im not sure what you are asking for. That site lists the parts he used and the issues he ran across. Are you wanting someone here to add this up for you?
Whats an inexpensive render farm mean to you? $5k, $10k? This is like saying you want to buy an inexpensive jet aircraft. The entry cost is still high relative to a single PC box/system.
How many systems do you think you need for what you are doing? 5? 10? 20?
Setting this up is relatively simple. Pay attention to the basics, find used parts for cheap and go...