Western Digital offers its factory-refurbished Western Digital 3TB My Book USB 3.0 External Hard Drive for Mac, model no. RWDBYCC0030HBK-NESN, for $89.99 with free shipping. That's $9 below our December mention of a new unit and the lowest total price we've seen for this drive. (It's a current low for a refurb by $20 and a low by $29 for new.) 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.