The Source has Engergizer Max C Alkaline battery 4-packs on sale for $5.49 (save $6.50 off) right now. If you use the friends & family coupon code 039362 you can save another 30% off bringing the price down to $3.84.
These are available for shipping online, or for free in store pickup.
They also have the 2 pack of 9V batteries and 4 pack of D batteries for the same price.