AcomData 500GB 2.5″ Portable External Drive eSATA / USB 2.0 for $99.99 shipped. This 500GB portable USB / eSATA hard drive gets its power through USB and does not require a separate power supply like most external hard drives. Ii is also smaller than most of them, making it much more convenient to carry around. Note that it also comes in a leather-style lined case for a more executive look. As a comparison, Amazon has this drive for $123.