As you probably know stevia and coconut sugar are two different things. Stevia is pretty much calorie-free while coconut sugar has the same grams of sugar as table sugar, however it has been stated to have a lower glycemic index making it a better choice to slow blood sugar spikes.
Coconut palm and coconut sugar are the same thing as I understand.
Stevia in the Raw is an example of a product you'll find on the market...it includes bulking agents, maltodextrin and dextrose which are carbohydrates derived from corn (that may be genetically modified).
I like the pure liquid stevia from here: https://www.omicaorganics.com/
Coconut palm sugar can be found in most health food stores. Just be sure to look for one without added fillers or bulking agents. http://navitasnaturals.com/product/447/Coconut-Palm-Sugar.html
It may also be called coconut nectar.
Thanks so much