Amazon has the SanDisk 400GB Ultra UHS-I Class 10 microSDXC Memory Card, model no. SDSQUAR-400G-GN6MA, for $56.99 (regularly $94.99) with Free Shipping for a limited time. B&H Photo has it for the same price for a limited time.
The SanDisk Ultra microSDHC Flash Memory Card performs with up to a 100MB/s transfer speed, offering the highest available speed rating in its class. With UHS Speed Class 1 (U1) and 400GB capacity, you can record Full HD videos seamlessly and get the most out of your mobile apps, photos and more. The SanDisk Ultra Flash Memory Card is definitely the ideal storage solution for your mobile content. It includes an adapter for full-size SD.