B&H Photo-Video offers the Western Digital 4TB My Book USB 3.0 External Hard Drive, model no. WDBFJK0040HBK-NESN, for $159. Coupon code "SHOPEB140" cuts the price to $129. With free shipping, that's $0.32/GB and the lowest total price we could find by $30. It features USB 3.0 connectivity, local and cloud backup, and up to 5Gb/s data transfer speeds.