Seagate STBF500101 GoFlex Satellite 500GB USB 3.0 Portable Hard Drive for $159.99 shipped.  Here is a screenshot for your reference. It features 8MB cache, built-in wireless 802.11b/g/n connectivity, USB 3.0/2.0 interface, automatic media and document syncing, and WPA security. Most places have it for about $179 or more.