I gave up on store bought flavoured sodas as a regular part of my life a good 20+ years ago but if your concern is that the purchased syrups aren't available or taste iffy just make your own. It's really not hard. Make a simple syrup and add the flav of your choice. I make my own ginger ale and control not only the amt of ginger used (I like a lil throat burn) but sugar amt. I don't have a soda machine just buy seltzer or club soda and add the flavour of choice.
Here's a site that can get you started:
http://imbibemagazine.com/How-to-Make-Simple-Syrupsbut simply googling flavoured sugar syrup will get you a ton of sites.
Been able to "brainwash" my DGD and at least one of my sons into into thinking soda is a treat as opposed to a G-d given right which is pretty much the way I was brought up. The other son thinks he was deprived by not having Coke and Count Chocula as a child but the last time he told me that I responded he was old enough to pay for his own psychiatrist's couch.....:W
HTH!