ohh cool, I've always taken my passport to immigration, because I popped in to ask a question and they wanted to see my passport when I said it was at home they told me off for not carrying it, so anyway I just take my passport.
Gosh, it depends on so many factors, age, medical history, what cover you want, if you want a bare bones insurance or high end. Is it related to your visa? Im sure your be contacted by insurance agents now you made this post