Amazon has the Oball Shaker by Kids II for the lowest ever price of $2.85. It is an add-on, but you can get around that by ordering with your Echo (if you have one).
The trick to order with Echo is to ask for a "ball shaker". I tried saying "oball" fifty different ways. She heard "oval", "oboe", "old ball". Very frustrating! But I beat her in the end!
https://www.amazon.com/Kids-II-81…B008J1QP7Y