A lot of cruisers do not have health insurance. You really need it in the US since the medical costs are so high but elsewhere not. My wife and I are basically quite healthy so decided not to get insurance. In two years these are the costs"
I have been fighting staph skin infections (fairly common in tropical cruising it seems) and have had three experiences}
1. clinic in Managareva, Gambier islands; went about five times; once to see doctor and the other times nurse to have dressing changed
2. fancy new hospital in Papeete, Tahiti and was treated by a doctor and 2 nurses for about an hour in total including have a boil cleaned out; cost about $60; prescriptions and various medical supplies $110 (French Polynesia is very pricey)
3. private hospital in Suva, Fiji (public hospital would have been much cheaper); doctor for about 10 minutes was about $16; prescription (oral antibiotic) $12
We have a pretty good first aid kit on board but should have had more sterile pads and an antibiotic specific for skin infections (Keflex for example). We had Cipro and apparently it is not that good for skin bugs. A doctor on another boat suggested we should have a more powerful painkiller (something based on morphine) in addition to the two prescription ones we have.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.