Western Digital offers its factory-refurbished Western Digital 3TB My Book USB 3.0 External Hard Drive for Mac, model no. WDBYCC0030HBK-NESN, for $89.99 with free shipping. That's tied with our June mention as the lowest total price we've seen for this drive. (It's a current low for a refurb by $20 and $29 under the best for a new one.) It works with Mac systems right out of the box and can be reformatted for Windows. It features USB 3.0 and 2.0 ports, password protection, and compatibility with Apple Time Machine. A 6-month Western Digital warranty applies.