I like sparkly drinks. for adults, on a hot evening sitting out by the pool or eating on the deck, I like a spritzer with plain seltzer and a dash of Pinot grigio. really makes the wine last longer and is very cooling. for the kiddos, we use the same seltzer with a dash of cranberry juice, or lemonade or both. Again, it isn’t pop, which I only let my kids have 2 or 3 times a year, and it isn’t as expensive or sugar filled as just drinking the lemonade or juice, and they think it is special because of the bubbles. I let them drink it from acrylic stem glasses and that adds to the fun. DH likes home brewed iced tea with a splash of raspberry syrup (the kind you see in the coffee shops, they sell it at a discount in Marshalls).

We buy the Old Orchard brand blueberry/promenganate and other combinations that are frozen 12 oz cans.  It’s usually about $1.50, sometimes $1 on sale.  We use half a can, mix with about an equal amount of water to mix it up.  Then we take a 1 liter of sparkling water or seltzer and top it off.  Voila!  Sparkly juice at half the cost, and less calories to boot!  It also cuts the sweetness.  We like to serve this with pasta meals to the kids while the husband and I drink our wine.

To stretch your juice, freeze it in ice trays and ratio those out into iced tea.

To make still water a little fancier, a local restaurant serves still water with lemon, lime, and cucumber slices.  The cucumber adds a little unexpected flavor that is very refreshing.

I love to mix 1 part lemonade with two parts sparkling water or iced tea.

I also like to mix equal parts iced tea, lemonade, and orange juice; serve with muddled mint leaves over ice cubes.

Sliced tangerines or mandarin oranges in a pitcher of ice water disappears like soda in my house.  I leave the pitcher out & add ice & water as needed.  You don’t need to add new slices of fruit each time you refill with water.

Like others mentioned, the best way to stretch juice is to add a splash to club soda.  I am a fizz addict.  Hence my many years of diet coke obsession.  I can get caffeine from tea.  The real thing I wanted was the fizz of the carbonation.  Club soda is great for that.

Summer Water!  I grew up in a house where summer water reigned supreme!  To a pitcher of water we’d add citrus slices (lime, lemon, tangerine, orange…)  - or maybe some melon slices (watermelon, cantelope, etc) with peppermint.  As we got older, we got adventurous - peaches and thyme - just fresh lavender - fresh basil leaves and cucumber… whatever is growing in the garden or looks good at the grocery store.  Let the kids experiment - it doesn’t cost much!

“Arnold Palmer"s and variations.  (For those of you who don’t know, that’s half iced tea, half lemonade.) The lemonade can be the cheapest kind—many brands sell it in a 2liter bottle for the same price as pop—and an added feature is that the tea then requires no sugar.  We’ve done it with regular lemonade, pink lemonade, limeade…  You could even make up frozen concentrated lemonade using the sparkling water trick above and have sparkling Arnold Palmers. I need to try that!

OK - I’m gonna shake things up a little here and offer up my favorite ADULT summer beverage….

Spring Fling
In a large pitcher, mix 1 1/3 cups sugar, 1 cup fresh mint, and 2 lemons and 1 cucumber sliced into thin rounds.  Add 2 cups each of vodka (you can use citrus flavored if you’re feeling fancy) and the juice of 10-12 lemons (bottled lemon juice works too).  Let stand for 30 minutes then stir to dissolve sugar. Chill.  Add 2 cups club soda before serving.  Serve over ice with lemon, cucumber and/or mint garnishes.

You can easily save any remains and just add more lemon juice, vodka and club soda the next day….

Cucumber limeade!  It’s really refreshing and great for guests—people will think you’re making something very fancy, when it’s really easy!  Note—best drunk immediately, as it tends to separate when left in the fridge for a while. http://www.marthastewart.com/318599/cucumber-limeade

Smoothies, smoothies, smoothies!
I keep a freezer full (ok, not actually ‘full’) of ziplo sandwich bags containing 2 (peeled) bananas each.
I dump the frozen banana in the blender.
I add about 16 oz of liquid (usually a vanilla soy milk, since we have dairy allergies)
Blend & serve to hungry/thirsty kiddos.
Sometimes we get crazy and add in some cake-topper rainbow “sprinkles” for fun (after poured in glass)
Sometimes I add in a soy yogurt, or a blop of tofu, or some cocoa powder, or other fruits (berries or peaches) or even soy ice cream. 
Sneaking in crushed vitamins & supplements (fish oil, flax oil, etc) is also acceptable!

Sorry for being days late on this thread! Our favorite cheap drink is lemonade from the can mixed with any flavor koolaid. It makes a huge pitcher full, and is cheap! But it tastes like the great stuff from a restaurant. They like any flavor mixed in, but watermelon kiwi has been a huge hit with kids and adults alike.