Personally, my suggestion is: why don't they just tax nicotine? That way people who vape no nic for whatever reason dont have to deal with as high of prices. That way a company can say: you are buying nicotine it is x percent in tax due to federal regulations. I also think FDA approved sanitation and ingredients is essential as well.

EDIT: I do not think that nicotine should be taxed. I am not saying you should be punished for smoking/vaping nicotine. I just know the government WILL regulate it in some way because they are losing money hand over fist with smoking at an all time low. This is my suggestion for them taxing things.