Adorama offers the Lexar 64GB Class 10 UHS-1 633x High Performance microSDXC Memory Card and USB 3.0 Reader for $43.95 with free shipping. (topelectronicdeals via eBay charges the same.) That's the lowest total price we could find by $33, outside of the price below. It features a maximum read speed of 95Mbps and a minimum transfer rate of 10Mbps
A close price: B&H has it for $44.99 with free shipping.