Walmart offers the Samsung 64GB EVO UHS-I Class 10 microSDXC Card with Adapter, model no. MB-MP64DAT/WMT, for $24.99. Opt for in-store pickup to avoid the $4.97 shipping charge. That's the lowest price we could find by $3, although we saw it for a buck less three days ago (since expired). It features data transfer speeds of up to 48MB/s.