There's been a guy selling inulin on other groups that I belonged to. He's been selling it for about 1 year now. So far, some say that they feel better, some say that it had no affect at all, and some are sensitive to it.
Even though he claims that it "cures" people, so far nobody has been "cured" using his inulin.
Inulin is also in some foods. From what I remember, chicory root is high in inulin. It's also in garlic.
If you're interested, doing a google search on inulin in foods may be a better way to go.