Western Digital ( WDC) drives down prices of external hard drives in its battle with rival Seagate Technology ( STX). The newest crop of hard drives offer twice the capacity at half the price of last year's models. The numbers. As a Black Friday special, Wal-Mart is offering the Western Digital portable 320 gigabyte external hard drive for $49, a 50% markdown from the $99 regular price. Seagate's popular FreeAgent 320-gigabyte external hard drive goes for $80. The stock. Storage has been a popular theme for tech investors this year. With component costs falling, manufacturers have been able to cut prices profitably as higher sales offset lower prices. Shares of Western Digital and Seagate have tripled this year.