Western Digital offers its factory-refurbished Western Digital My Passport Essential 320GB 2.5" Portable USB 3.0 External Hard Drive in Black, model no. WDBACY3200ABK-NESN, for $49.99 plus $2.99 for shipping ($0.17/GB). That's $19 under the lowest total price we could find for another refurb, although we saw it for $12 less last fall. It features an 8MB cache, maximum data transfer rate of 5Gb/s, and backward compatibility with USB 2.0. A 6-month Western Digital warranty applies.