Element, unless you are using some strange form of math, 4 x 250 GB = 1 TB not 100 TB.
And between the cost of 4 SATA HDDs and the server, you are way over the $1200 list cost of this. And there's the issue of space, this is very compact, far more so than your server.
Pretty interesting comment on the cost of HDD storage, $1.20 a GB. My first 40 MB HDD, just 15 years ago, cost over $500 or about $12,500 a GB. That's a major price drop. Wish everything else had done that (except my income).