NordicTrack NTFB7511 75 cm Exercise Ball (Silver) for $8.99. Order online for in-store pickup at Sears to lock in the price and save on shipping.  Otherwise, shipping is $7.75 for a total of $16.74 shipped. Here is a screenshot for your reference. It has a 300-lb. weight capacity and is designed for people with heights over 5'-11".