Buy.com is offering the Dane-Elec 2GB secure digital memory card (model no. DA-SD-2048-R) for $4.95, which is $15 off the list price of $19.95 and the lowest price we could find on this memory card by just over $4.  FREE shipping is included and sales tax applies for residents of New York and California.
 

The Dane-Elec 2GB secure digital memory card is designed for use with personal assistants, PDAs, MP3 drivers, mobile phones, and also with digital cameras and camcorders.  It has a data transfer rate of between 2MB and 4MB per second.  Dimensions: 32 mm x 24 mm x 2.1 mm; weight 0.07oz.