Today only, Amazon offers its Amazon Prime members the Kingston Ultimate X 16GB SDHC Class 10 Secure Digital High-Capacity Card, model no. SD10G2/16GB, for $19.99 with free shipping ($1.25/GB). (Non-members can spend over $25 for free shipping; otherwise, shipping adds $5.58.) That's $5 under our June mention and the lowest total price we could find by $5.

Amazon Prime membership is $79 per year; however, Prime is free for college students for one year, and free for parents and caregivers for three months.