Amazon offers Prime members the Transcend 16GB SDHC Class 10 Memory Card, model no. TS16GSDHC10E, for $5.99 with free shipping. (Non-members can qualify for free shipping with orders of $35 or more; otherwise, shipping adds $8.02.) That's the lowest total price we could find by $2 and the best price we've seen. It features read/write speeds up to 30MB/s.