This deal has ended.
Buy.com has the Cavalry 500GB USB 2.0 External Hard Drive priced at $99.99, after a $20 mail-in rebate (through 4/1). Shipping is free and there is no sales tax (except CA, MA, MD, TN). $0.20 per gigabyte is a great deal on external storage, and this particular drive has received 4.5 out of 5 stars from over 150 buyers. New Google Checkout users can get an additional $10 discount for signing up.