Angelika, great question.
I went googling and found this forum from 10 years ago, but I think the information is still relavent.
http://forums.gardenweb.com/discussions/2012906/selling-herbs-worth-it
Some of the information covered aspects such as, for them anyway, like needing a grocer permit, displaying fresh vs. dry, whether it was profitable.
.
If you are good at wildcrafting herbs and edible plants, I have a better idea for you, with less regulatory red tape and more
profit. Hold small wildcrafting parties, where you teach locals how to find and use herbs for medicinal and cooking. I say cooking, because evidently Australia has awesome herbs to spicy up your food. You could do videos of your trips to extend your reach, sell to organic and
sustainable types continent wide.
You might market videos and guides through sites similar to this one, they do a nice interview of you and your information, you give them a healthy piece of the pie.
In the beginning you could charge less to get your act polished, then when you're doing it in your sleep,
video record it. The video needs to inform, make sure sound quality is good.
Hope this helps.
Mike