I never had insurance before 37 years old. I just didn't need any coverage. At 37 I got pregnant, so I signed up for Tricare because I was enlisted in Army reserve. I paid zero dollar for pregancy and birth, and the insurance itself. Zero!
I don't know anyone younger than 35, healthy and not preganant would need to buy medical insurance. Just go to ER when very sick for something. They will have to treat you!