$40 for a 64GB micro sd seems pretty good if it works with SG3? I've heard rumors and read some things here about Samsung making it difficult for non-samsung made micro sd cards working on it?
SanDisk Mobile Ultra 64GB MicroSDXC Flash Card Model SDSDQUA-064G-A11A
Newegg.com - SanDisk Mobile Ultra 64GB MicroSDXC Flash Card Model SDSDQUA-064G-A11A
SanDisk Mobile Ultra 64GB MicroSDXC Flash Card Model SDSDQUA-064G-A11A
Newegg.com - SanDisk Mobile Ultra 64GB MicroSDXC Flash Card Model SDSDQUA-064G-A11A