Western Digital My Passport Essential 500GB Portable Hard Drive for $104.88. It is also available in Blue, Red and Silver. Pick it up at a Walmart near you using free site-to-store shipping. Otherwise shipping is $6.97. This 500GB portable USB hard drive does not require a separate power supply like most external hard drives and is also smaller than most of them, making it much more convenient to carry around. It usually sells for over $145.