Newegg offers the HGST Deskstar 4TB NAS Serial ATA 6Gb/s Internal Hard Drive, model no. H3IKNAS40003272SN, for $159.99. Coupon code "ESCEFEN23" cuts it to $139.99. With free shipping, that's the lowest total price we could find by $20, although it was $10 less on Black Friday. This 7200rpm hard drive is designed for NAS systems and features a 64MB cache. Deal ends January 10.

Note that this is the bare drive.