Amazon offers Prime members the Silicon Power 64GB UHS-I Class 10 microSDXC Memory Card with Adapter, model no. SP064GBSTXBU1V20SP, for $21.99 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping adds $8.) That's the lowest total price we could find by a buck. It features transfer speeds of up to 85MB/s.