You don't need class 10! because this is not a super professional camera. Class 4 is enough (in some case even class 2 is enough 'cause some people say that class 2 speed of some manufacturers is faster then class 4 of other ones).
I have ordered SanDisk class 4 32gb and still wating for delivery...
Choose only good manufacturers, such as: SanDisk/Trancerd/Kingston/A-Data (and before doing an order, check on their official website (and google a lil' bit) if the particular class exist - for example if you will see class 2, 6 or 8 of Kingston on ebay, know that it's a fake since kingston has only 4 and 10 classes according to their website)