64GB SanDisk High Endurance U3 microSDXC Memory Card Pre-Order
Amazon.com has 64GB SanDisk High Endurance V30 U3 C10 microSDXC Memory Card w/ Adapter Pre-Order (Sdsqqnr-064G-GN6IA) for $14.99. Shipping is free w/ Prime or orders $25+. Thanks blackvtec01 and commemoratives
Amazon.com also has 128GB SanDisk High Endurance V30 U3 C10 microSDXC Memory Card w/ Adapter Pre-Order (Sdsqqnr-128G-GN6IA) for $25.99. Shipping is free.
Note: These cards will be released on April 26, 2019. Refer to the forum thread for additional deal ideas.