BuyDig offers the Western Digital 4TB My Book Essential USB 3.0 External Hard Drive, model no. WDBACW0040HBK-NESN, for $169. Coupon code "VMESAVESU20" cuts it to $149 when you pay via V.me by Visa. With free shipping, that's $0.04/GB and tied with our December mention as the lowest total price we've seen for this hard drive. (It's a current price low by $21.) It features USB 3.0 connectivity, automatic backup, and more. Deal ends March 31.