By Amy E. Feldman

PHILADELPHIA (CBS) - Every insurance commercial I’ve ever heard offers to save me 15% on my car insurance. On the 7th switch do I get it for free?

There are many different forms of car insurance, and each may be purchased separately or wrapped together as a bundle of protection. So you could save money, but that’s by getting less insurance coverage.

By law in virtually every state, you must carry liability coverage that covers injuries that you cause to someone else.

Personal Injury Protection coverage which is not generally mandatory is what pays for the medical costs of the driver and passengers in the policy holder’s car.

Then there is collision coverage for damage to your car, and comprehensive coverage that reimburses you for loss due to theft or damage caused by something other than an accident.

So even though you might save money up front, ask what the insurance you’re paying for really covers (your medical costs? Lost wages? Harm to passengers?) – and then figure out if paying less now is a risk worth taking in the long run.