This deal has ended.
Today only, Buy.com has the 500GB Fantom Titanium-II USB 2.0 External Hard Drive priced at $79.99 after a $20 mail-in rebate (expires 4/30). Shipping is free and there is no sales tax (except CA, MA, MD, TN). $0.16 per gigabyte is a great deal on external storage and it comes with a one-year warranty. Plus, new Google Checkout users can get an additional $10 discount for signing up.