Sites like HealthCare.gov allow you to compare private plans and see if you qualify for subsidies based on your income.
Understanding these costs helps you avoid "sticker shock" when you actually use your insurance: How to Buy Health Insurance for the First Time | Anthem buying health insurance for the first time
In the U.S., you can typically stay on a parent's plan until age 26, even if you are married or graduated. Sites like HealthCare