Came in to mention this. My friend is gaga over it, and the True Lemon.
If you have access to fresh mint, it makes a very refreshing beverage even without sugar.
Ginger beer! Grate some ginger, heat it up to boil then let it sit. Add brown sugar. Chill.
Grape Drink…
Water + Sugar + Purple 
Strawberry or raspberry lemonade.
Cherry limeade.
If you a little sliced fresh ginger to the lemon and cucumber you have “Sassy Water”, one of my staples. Very refreshing.
TrueLime and TrueLemon are wonderful just dropped into a glass of icewater. Shockingly close to fresh juice without all the mess or the risk of getting bad fruit. I didn’t like the orange one though - tasted like chidren’s aspirin.
Third or fourth the suggestion of making a pitcher of herbal iced tea. There are a zillion flavors to choose from, and it’s very tasty and economical. Celestial Seasonings Mandarin orange spice is one of my favorites. Also Bigelow Raspberry Royale which has a touch of caffeine, but not so’s you’d notice. Both taste sweet without added sugar.
If you really want to spoil yourself, Teavana’s dessert teas are really like a spoil-me snack, without any calories at all. I especially like the Almond Cookie.
I need a new drink
One that won’t make me drunk
One that won’t make me crash my car
Or make me act like a punk
If you live near a Wegmans they sell Frizzante European sodas, Sicilian lemon, cranberry lime, and blood orange. (maybe Amazon carries it). YOWZA! Intense stuff! Not like ordinary soda at all. I dilute this with fizzy water.
Cranberry juice with club soda and a hit of lime. Not too much juice. That’s my perfect summer no booze refresher.