This 9" Underwater Watermelon Ball, on sale for $24.99, drops to $19.99 when you click the on-site coupon at Watermelon Ball via Amazon. Shipping is free when you use a Prime account or free Prime trial. Shipping is also free when you spend $25 or more. Otherwise, it adds $5.99. This sells for $45 or more elsewhere. This ball includes a hose adapter. Once the ball is filled with water, it's able to be bounced and passed underwater as well as float to the top. Sales tax is charged in most states.