For most of us, auto insurance is a big expense - drivers under $25 years old, for example, can end up paying $200 a month or more just to insure their vehicles.

Some companies do offer cheap car insurance, but it's important to be careful when dealing with these companies. You don't want to end up in a situation where your car insurance doesn't cover your claim, or doesn't pay all of your expenses if you have an auto accident.

Before you buy a car insurance policy, here are 5 crucial questions you should ask your agent. Asking these questions can save you a lot of headaches, and will help you avoid buying a policy that won't meet your needs:

1. What does my policy cover? Don't assume that your insurance company will replace your car if you have a bad accident. Some companies quote liability-only policies just so they can give you the lowest price possible. It's not worth it if you're stuck paying off a car that has been totalled in an accident.
2. If I have an accident, who do I call? Some companies make it difficult to file a claim - they're banking on the fact that you'll eventually give up. Get the phone number for your local adjuster before you pay a penny for the policy - this can save you a lot of stress down the road.
3. How do I qualify for discounts? Most companies offer a variety of discounts - but they don't always tell you about them. Make sure you find out how to qualify for every discount available, so you can reduce your expenses without sacrificing coverage.
4. Are there any restrictions on how I use my car? Each insurance company places restrictions on how your car can be used - for example, some companies won't cover you if you're driving to meet clients for work or business. Find out exactly what you can and can't do, so you don't end up getting a claim denial letter later.
5. What happens if I cancel my policy? Insurance companies have different rules regarding how your unpaid premium will be refunded if you cancel your policy. Some charge a hefty "cancellation fee", while others use a "short rate" method, which means that they get to keep a percentage of your premiums, even if you cancel your policy the same day you buy it. If you find a better deal and cancel your policy, you can end up losing quite a bit of money.