Newegg has the Kingston 4GB Secure Digital High-Capacity (SDHC) Flash Card for $12.35 - $2.36 Code: EMCAKACCB = $10 with free shipping

List Price: $15.25
Mail in rebate /Discount: - $2.90
Sales price: $12.35
Price After Rebate: $10 after code discount

Technical Details:
Model
Brand Kingston
Model SD6/4GB
Type Secure Digital High-Capacity (SDHC)
Tech Spec
Capacity 4GB
Speed 6MB/sec
Features Class 6
Products designed exclusively to support previous SD specifications 1.0 and 1.1 will not be able to utilize SDHC cards.
SDHC devices should be able to support standard SD cards. Because of compatibility concerns, customers should look for SDHC logo
on cards and host devices.
Manufacturer Warranty
Parts Lifetime limited
Labor Lifetime limited

Link to the buy: Newegg.com
Rebate form: Code EMCAKACCB