How can I find a reasonable health insurance policy?

I’m going to be taking a semester off from school this coming fall and my step-father’s health insurance only covers me as long as I am a full time student, otherwise it’s $400 monthly. I just need something to cover me for five months until I’m a student again. I’ll be living either in Ohio or California—not sure which yet. So… how can I find insurance? I’m young, with no outstanding medical issues.