Plain old fashioned powdered fruit ade drinks are still inexpensive. Add your own sugar to save money. You can sometimes find packets of lemonade or other flavors on sale; stock up if you can because it also makes excellent snowcone types of treats. To do that, mix it with half the water it calls for and all the sugar. Crush ice or, if you have a powerful blender, make snowcone consistency, then pour the ade over the ice.
Real lemonade is not expensive, if you start with fresh lemons. Heat them, then roll them against the counter while they are still hot and you will get the maximum amount of juice. Pick out the seeds if there are any, and add water and sweetener to taste. A little lemon juice will go a long way, so don't overdo it. A couple of lemons will make several glasses of lemonade.
Tea is always a good choice, but if you don't want the caffeine, buy decaffeinated tea. Loose leaf tea makes the best iced tea, but it's hard to find so make it with teabags made for hot tea. You can buy a box of 48 teabags for around $3.00 and that's pretty frugal.
It will take one teabag per glass. Heat a cup or two of water to boiling and pour over the teabags in a cup or other heat safe container, let it steep for at least five minutes, then remove the teabags and add water to equal as many cups as there were teabags. Add sweetener if you want it and pour over ice.
If you still want sodas, think about getting a Sodastream. No, it's not frugal, by the time you buy their syrups, but there are ways around that. Those inexpensive packets of fruit ade come in a great variety of flavors. If you make a syrup and add the flavors to it, you can use that to make a carbonated beverage with a SodaStream. After the initial cost, you can get some pretty cheap sodas.
Even if you buy the syrups to make special flavors like root beer and cola, it can be cheaper. Use it to make root beer floats or "coke floats." Remember those? They cost a pretty penny now, but you can have those treats a lot cheaper.
