Amazon has a 12-Pack of Gatorade Zero Sugar Thirst Quencher, 20 fl. oz. Bottles (Lemon-Lime) for $7.30 - 5% off with Subscribe & Save (can cancel at any time) = $6.94 with free shipping on $25+ or with Prime. The Regular (full sugar!) version in the same flavor is just slightly more after S&S.
$6.94 retail: $13Report