Amazon offers the Seagate FreeAgent GoFlex 500GB Portable USB 3.0 External Hard Drive, model no. STAA500105, for $49 with free shipping ($0.10/GB). That's $1 under our mention from last week and the lowest total price we could find by $21, outside of the price below. This drive runs at 5400 rpm and features an 8MB cache.

A close price: Walmart has it for $49 plus 97 cents for shipping. (Free Site-to-Store is also available.) Sales tax is added where applicable.