Amazon has the SanDisk Extreme 64GB UHS-I microSD Card with Adapter (SDSQXA2-064G-GN6MA) for $14.49 with free shipping for Prime members or on $25+. Features up to 160MB/s* read speeds to save time transferring high-res images and 4K UHD videos(2). Requires compatible devices capable of reaching such speeds, up to 60MB/s write speeds for fast shooting.* Requires compatible devices capable of reaching such speeds.
Has excellent Amazon Reviews.