Amazon offers Prime members the SanDisk Extreme Plus 64GB UHS-I/ U3 Micro SDXC Memory Card, model no. SDSDQX-064G-AFFP-A, for $34.99 with free shipping. (Non-members can pad their orders to over $35 to qualify for free shipping; otherwise, it adds $8.02.) That's the lowest total price we could find by $29. It features read speeds of up to 80MB/s and write speeds of up to 50MB/s.

Of note, Best Buy offers the similar SanDisk Pixtor Advanced 64GB UHS-3 Micro SDXC Memory Card, model no. SDSDQX-064G-AB46A, for the same price with in-store pickup.