Amazon has a 12-Pack of C4 Energy Sugar Free Pre Workout Energy Drink Cans, 12 fl. oz. Cans (Frozen Bombsicle) for $21.83 - 35% off coupon (first S&S order for this product) - 5% off with Subscribe & Save (cancel anytime) = $13.10 with free shipping on $25 or with Prime.

Purple Frost and Tropical Blast are also available for slightly more.