Instead of buying soda that has a ton of chemicals and HFCS, make your own.
Save the parts of the fruit you wouldn't eat such as the peels of oranges or the core of pineapples. Collect it in a zip lock bag that you keep in the freezer. Once you have enough or are ready to make some soda, buy some club soda. If you're a big soda drinker, it is more cost effective to buy the 2 liter bottle but if not, the cans are better so that you avoid wasting your soda.
Put your fruit scraps in a medium sauce pan. Cover it with sugar. You're going to use quite a bit since you're making a syrup. Add enough water to submerge the sugar. Put on medium heat for 15 minutes and then check the thickness of the mixture. Stir and heat for another 15 minutes if necessary. After you're done heating it, add the syrup to club soda. Add as much as you want. Taste it to see how sweet you like it.