[reemrevnivek]

You need to go back to the top of the page (not the "related posts" at the bottom ... >_>) and find part 3:

http://bioteam.net/2011/08/real-world-backblaze-costs/

Projected cost from Backblaze was $7384, for drives at $120 each and other parts sourced in quantity. A lot of the expense for these guys came from the $5400 everything-but-the-drives kit from Protocase.

The drives were more expensive because a certain model of 3TB Hitachi drives are the parts recommended by Backblaze; they didn't get whatever happened to be on sale at Newegg that day. The drives were supposed to be $120 each in Backblaze's quantities. They ended up finding a sales rep at CDW.com who sold them for $129 in quantity, but they were more expensive elsewhere.