Amazon has the deal of the day SanDisk Ultra 64GB Dual Drive m3.0 for Android Devices and Computers (SDDD3-064G-G46)
For $14.99 was $23.49
Free up space on your OTG-enabled Android phone
Back up your mobile photos, videos and contacts
Retractable design with dual micro-USB and USB 3.0 connectors
High-speed USB 3.0 performance with up to 150MB/s file transfer from drive to computer
SanDisk Memory Zone application (available on Google Play) lets you easily manage your photos and videos