B&H has a solid deal on a SanDisk 64GB SDXC Class 10 card right now for just $48.95. The email I received said it was a “weekend” deal, but I’m not sure of the exact expiration. Check it out here at B&H.
Class 10 cards deliver on speed for HD video capture, which goes along with the size advantage of the SDXC spec. For more details on what all the classes and card specs mean, check out my resource article Demystifying SD Cards.