Both B&H and Adorama have the Lexar 128GB 400x Class 10 SDXC card for $119.95 now through June 7, 2013 (reg. $199.95). Check it out here at B&H Photo and here at Adorama.
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.