Amazon.com has Fisher-Price Rock-a-Stack for $5.00 with free shipping on orders over $25 or with Amazon Prime orders.
From grasping and shaking to sorting and stacking, the Fisher-Price Rock-A-Stack has tons of fun ways for your baby to play and explore. Babies can sort and stack all five rings, then bat at the wobbly base to see what happens, helping to enhance their curiosity and sense of discovery.