There are 3 or 4 large health insurance companies here - Universal, Humano, Palic (?) and maybe one other.
For specifics about coverage, best to speak to an insurance broker or the companies directly. Costs are on a sliding scale based on the coverage you purchase. As with most insurance, purchase as much as you can afford as needing it and not having sufficient coverage pretty much negates having coverage in the first place. It is hoped that you pay, but never have to use.
All of the companies have a a maximum age for new customers which I believe is around 64 years old. The younger and the heather the person is, the lower the yearly premium. All plans offer limited coverage for at least the first year.