Most of the recipes use a simple syrup or honey to sweeten the sodas.
If you don't want to use refined cane sugar you can use Raw cane sugar, stevia or coconut palm sugar or any other type of powdered sweetener in place of the cane sugar.
For those calling for using honey you can substitute agave or one of the nectars such as apricot nectar.
To make any tea or fruit juice fizzy you just add seltzer or club soda to the syrup base.
You can also buy soda siphons to make your own seltzer.
I have tried a lemon verbena tea soda just adding the store bought seltzer to it. Works great and the flavor is still lemon verbena.
If I was going to use honey I would just infuse the honey with the herbs. This is much more beneficial than heating the mixture because heat destroys some of the nutrients in herbs.
If doing this method add your herbs to a pint jar then fill with raw honey. Preferably in a dark colored jar or put a paper bag around the jar. Sunlight destroys some of the benefits of honey so I wouldn't follow the instructions for doing this I've seen recommended just about everywhere to put it in direct sunlight without some means of blocking the sunlight from reaching the honey. I really don't see the need for putting it in sunlight anyway. Since all it really needs is a warm dark place to infuse for 4 to 8 weeks depending on how strong you want the flavor.
Linda you are most welcome to my thought provoking posts.
As a side note you can also use fruit to make soda.