WD Red 2TB NAS Hard Drive – 5400 RPM Class, SATA 6 Gb/s, 64 MB Cache, 3.5″ – WD20EFRX $63 FS

Lowest price I have seen for this. $62.99 Free Shipping from Amazon. $80 and above elsewhere.
Make sure you buy the one sold and shipped by Amazon to get full 3 year warranty.
https://www.amazon.com/Red-2TB-NA…B008JJLZ7G