Go in through this link.
Scroll to the bottom to "Internal Hard Drive Storage"
Select WD Red NAS Hard Drive
Make Sure Form Factor is at 3.5
Select 8TB from the drop down
Add to Card should appear, if not then its all gone and these go fast.
4 TB: $95.99 *sold out*
6 TB: $153.59
8 TB: $198.39 *sold out*
These have 3 YR Warranty and are straight from WDC.
Reference prior thread, prices now a little better: https://slickdeals.net/f/10029672-8tb-western-digital-wd-red-nas-3-5-hard-drive-wd80efzx-for-210-edu-email-req#commentsBox
re: Why is this a good deal:
This comes up in every thread on WD Red drives, which are specifically for NAS setups. The 8 TB drive is $290 all day at every major vendor. Most people buy 2-4 of these at a time, so thats ~$180-$360 off. I doubt you will get a better deal than this on these drives in the next few years @$25/TB for a bare red drive that you don't have to harvest from an external drive and hope for the best.
These prices are as low as WD Red drives have ever been, and likely will be for the near future. Red drives have held their value and not come down in price over the last few years.