https://sport.woot.com/offers/penn-championship-tennis-balls-12-cans?ref=w_cnt_sc_is_1_tl 12-Pack 3-Count Penn Championship Regular Duty Felt Pressurized Tennis Balls for $12.99 - 10% w/ code SAVE10 at checkout = $11.69. Shipping is free for Amazon Prime Members (must login with your Amazon account and select a shipping address in order for Woot to apply free shipping) or is otherwise $6 per order.