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 September mention as the lowest total price we've seen for this drive. (It's a current low for a refurb by $20.) 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.