If you're looking for a refreshing drink without sugar/salt/caffeine you should try vinegar. I don't know how available it is in the U.S. but it's kind of normal to see a shelf of vinegar drink boxes in the convenience store here.
The one I like is black vinegar (kurozu, I don't exactly know what that is) with 2% ume juice. It's kind of sour at first but really if you like sour candy/fruit at all you'll probably like this. Also I think its health benefits will cure you of almost anything, at least psychosomatically as long as you don't research exactly what it does for you. (Hint: does not cure procrastination, laziness, denial of impending move, etc)