Amazon has the Organic Toddler Mum-Mum Strawberry Flavor Rice Biscuit, 24-Count Box (Pack of 6) for $15.94 and with free shipping when you sign-up for the Subscribe & Save option. You can also use code MUMMUMB3 at checkout to get an additional 35% Off making them $9.38 shipped for 6 boxes.
Offer should be valid through 6/30/11. Note: Right now they will not be in stock until 6/17/11 but you can still order them. Keep in mind that prices flip fast on Amazon, though.