This is back live @ $24.89 (or $22.90 from Amazon Warehouse) - https://www.amazon.com/gp/product/B003EV6MIG

Maybe something like this? I am using Amazon because it was the easiest link to find. You may be able to find it at Walmart or another local store.

Kamado Joe KJ-SCS Classic Grill Expander https://www.amazon.com/dp/B003EV6MIG/ref=cm_sw_r_cp_api_i_S72SGCBTQA0NND5Q5PV7