So this is a freebie with an extra step, but if you're feeling parched and only vitamin-enhanced liquid will do the trick, you'll want to pay attention. Ralph's grocery stores has a printable coupon for $1 off a Vitamin Water, and Vitamin Water is currently $1 at Target on sale. So you print the coupon, take it to Target (it's a manufacturer's coupon, so it's good anywhere), and hey presto! Free beverage.
I'm not generally big on coupon clipping, but when the coupon makes it free, that's a whole different story. Glug glug!