newegg.com offers the Kingston 4GB microSDHC Class 4 Secure Digital High-Capacity Card with Secure Digital Adapter
, model no. SDC4/4GB, for $6.99
with free shipping
($1.75/GB). Outside of the mention below, that's the lowest total price we could find by $1. (However, we saw it for a buck less last month.)
A close price: B&H Photo-Video charges $7.49 with free shipping.