Fry's Electronics via Google Express [google.com]
has WD NAS 3 TB Internal HDD - 3.5" - WDBMMA0030HNC - SATA 6Gb/s for $79.20 + tax when you follow the steps below. Shipping is free.
Note: You must check out with the Google Express App in order to apply and use the promo code.
Download/install Google Express App (iOS [apple.com]
or Android [google.com]
In the app, search for "wd red 3tb" sold by Fry's Electronics. The Fry's Electronics listing may come up showing their WD NAS 2 TB for $84.99, but you'll see "More options" over the image for the listing so simply click on it and change capacity from 2 TB to 3 TB where they'll have it on sale for 9% off bringing the price down from $109.99 to $99.
Apply 20% Off promo code APPFEB20 at checkout (Max of $20 Discount; more info)
Total will be $79.20 + tax & Free Shipping
Mine came out to a total of $89.35 after tax which is a reasonable price for this NAS HDD as they do not dip below $100 all too often.