BuyDig offers the Samsung Plus 64GB UHS-I Class 10 microSDXC Memory Card (pictured), model no. MB-MPCGC/AM, for $37.99. With free shipping, that's the lowest total price we could find by $18. It features transfer speeds of up to 48 MB/s.

Also available is the Samsung 16GB UHS-I Class 10 microSDHC Memory Card with SD Adapter, model no. MB-MGAGBA/AM, for $16.99. With free shipping, that's the lowest total price we could find by $5. It features 70MB/s read speeds and 20MB/s write speeds.