Western Digital Store offers its factory-refurbished Western Digital 4TB My Book USB 3.0 External Hard Drive, model no. WDBFJK0040HBK-NESN, for $109.99 with free shipping. That's tied with our May mention and the lowest total price we've seen. (It's also $20 under the best price we could find for a new unit.) It features local and cloud backup and up to 5Gb/s data transfer speeds. A 6-month Western Digital warranty applies.