Walmart offers the Uncle Milton Ant-Man Ant Farm, model no. 18420, for $14.09. (Sears charges just pennies more with in-store pickup.) Choose in-store pickup to dodge the $4.97 shipping fee. That's the lowest price we could find by $8, outside of the mention below. It includes sand, connector tubes to other habitats, and information to order live harvester ants online.
A close price, Toys"R"Us has it for $14.99 with free in-store pickup.