A best bet is to buy two Ball Wide Mouth Pint 16-oz. Mason Jar 12-Packs (one pack pictured), model no. 11132711, for $14.98. Choose in-store pickup to evade the $6.10 shipping fee. That's $21 under the lowest total price we could find for this quantity elsewhere.
Update: Coupon code "OFFERS10" cuts an additional 10% off, cutting the price of the two 12-Packs above to $13.48.
Ball Wide Mouth Pint (16-oz.) Wide Mouth Jars, Set of 12 is also available at these stores