Don't know whether this link(s) has been posted before....
Cheap RS-MMC memory cards. Not sure about compatability, but i will give them a shot at some point.
http://www.7dayshop.com/catalog/product_info.php?manufacturers_id=&products_id=99288
&
http://www.7dayshop.com/catalog/product_info.php?manufacturers_id=&products_id=99289
&
http://www.7dayshop.com/catalog/product_info.php?manufacturers_id=&products_id=99290