Tosh
Depends how much you want to pay out and MB size of card, for e.g Jessops (photo dealer) do a 80x max speed/150 KB/s 512MB SD card for £64.99 up to a 2GB card for 159.99
SanDisk do a 60x 512MB £53.99 they also do a 133x high speed 1GB card £124.99
Rick