Amazon has PNY SD and microSD cards on sale for Cyber Monday Deals Week. All of the SDXC cards are Speed Class 3 (aka U3) rated so they will work with the newer cameras that record compressed 4K video to an internal card. Check them all out here on Amazon.com.
To learn more about SD cards and what all the formats and designations mean, check out this article on Demystifying SD Cards.
Check out more great deals on our Black Friday and Cyber Monday Camera and Photo Deals page.