Amazon has the Samsung 128GB EVO Select UHS-I U3 microSDXC and Samsung 64GB EVO Select UHS-I U3 microSDXC on-sale, for $28.99 and $15.99 respectively. These cards come with an SD adapter so you can use them like normal SD cards. These cards are a decent speed — they are rated U3 for a minimum 30 MB/s write, up to 90 MB/s. The micro form-factor allows you to use these cards in other devices.
Amazon: Samsung EVO microSD U3 100 MB/s, 128GB $29, 64GB $16
