I have a few Sandisk, Patriot & Kingston cards. All perform great!
Patriot - 16GB Class 10 $23.99 (newegg)
Patriot - 8GB Class 10 $8.99 (newegg)
Kingston - 8GB Class 4 $11.48 (amazon)
Sandisk - 8GB Class 4 $9.99 (newegg)
I also have a few Transcend SD cards that work very well.
As long as you get a class 4 or higher, you should be fine. Class 2 cards work fine, just a little slower. Look on Amazon or Newegg for good prices. Looks like the 32GB cards start out around $45-$50 and go up from there.