Amazon has a great deal on Transcend SD cards right now. A 16GB Class 10 SD card is only $15.98 at the time of this post. Check it out here on Amazon.
The Class 10 rating is a rating intended for evaluating video capture performance. In this case, Class 10 is the fastest rating currently available for video performance, which means these will work with just about every HD video camera on the market today. For a more detailed explanation of SD card classes and speed ratings, check out my prior article on Demystifying SD Cards.