Before you purchase insurance, here are some clarifying points to help you get started:
You can purchase insurance for most things, and many of those decisions will be up to your discretion according to what your needs are. However, there are a few that are considered necessities: Auto insurance, Health insurance, Homeowners/Renters insurance, and Life insurance. Any others would need to be considered carefully based on what you can afford.
These are terms dealing with health insurance. A deductable is the amount you pay out-of-pocket for medical services before your insurance policy kicks in. A premium is how much it costs for you to maintain your policy. A copay is the fixed amount you pay for a health care service, usually during a visit to the doctor's office or filling a perscription for medication. This is considered cost sharing – when both you and the insurer pay toward your healthcare expenses.
In some cases, yes. For instance, sleeping in your car regularly isn't enough to make it a residence. But if you were to have someting like an RV – with areas for sleeping, cooking, and toilet facilities, it can then officially be declared a residence. At that point, you would need to get an additional homeowner's insurance policy along with your auto policy.
Even with as many insurance policies that are out there, chances are you won't find one that covers everything involving one particular area. For example, there are many health related services that are not covered through health insurance. Car insurance covers damages due to an accident, but it doesn't cover routine repairs. Damages brought on by earthquakes and floods aren't covered through homeowners insurance. This doesn't mean these policies are bad – it just means you have to choose wisely. Your goal should be to find the most comprehensive insurance policies in the most important areas for you.