This deal has ended.
Buy.com has two good deals on fast memory cards. The Viking 512MB 33X secure digital card, shown here, is $15.99 after a $13 mail-in rebate. The larger 1GB version is $24.95 after a $25 mail-in rebate. Inventory is limited on both of these cards. Shipping is free on both and there is no sales tax (except CA).