BuyDig offers the Samsung 4GB microSDHC Class 4 Secure Digital High-Capacity Memory Card with Adapter
, model no. MB-MS4GA/US, for
. Coupon code "FIRST2K" drops it to
. With free shipping
, that's $0.87/GB and the lowest total price we could find by $3. It's purportedly water- and shock-proof.
Update: It's now $8.49 before the above coupon, $3.99 after it.