I think health insurance doesn't work when overseas for an extended period, so I didn't have health insurance for 6 years since I was traveling through multiple countries. I bought travel insurance instead but never really made any claims except for lost baggage. It was around $350 per 6 months. They wouldn't cover preexisting conditions and I think only covers acute conditions, so not chronic or cancer. If you got an injury that spanned 2 different 6 month policies, the injury would not be covered in the 2nd 6 month policy because they would claim that it became a preexisting condition when the 1st 6 month policy expired.
I'm now in Europe for a few years and I think foreigners with temporary visas don't really quality for public health insurance. The private health insurance is expensive. So I bought something marketed to expats which still meets all the local mandatory cover but for only $100 per month with $1000 annual deductable, or excess as it's called in the rest of the world.