Lexar has some good deals on high-speed memory cards, at authorized dealers (Adorama, B&H, and Amazon).
On sale are their fast UHS-II bus, U-3 speed class SDXC cards, rated up to 150 MB/s. Canon cameras today do not use UHS-II but are these cards are backwards compatible to UHS-I. Also on sale are UDMA-7 compact flash cards, rated up to 155 MB/s.