How old does one have to be to buy Health Insurance?

You need to be an adult, legally, to buy it - 18. But since the health reform act, in most states, no insurance company will sell you a stand alone policy, until you are 19 years old.

Additionally, whatever is wrong, that you already NEED it, isn't going to be covered, most likely.

Your best bet is to get a job with health insurance benefits, and get it that way.

If you go to a college that offers a group plan to the students, then yes.

Normally, no. Most health insurance companies no longer sell to anyone under 19.

You need to be 19, so you would have to refer to your parental units.