Walmart offers the Seagate FreeAgent GoFlex 500GB Portable USB 3.0 External Hard Drive, model no. STAA500105, for $49 plus 97 cents for shipping ($0.10/GB). (Free Site-to-Store is also available.) That’s tied with our mention from two weeks ago as the lowest total price we’ve seen for any 500GB portable USB 3.0 hard drive. (It’s also a current price low by $18.) Sales tax is added where applicable. This drive runs at 5400 rpm and features an 8MB cache.