Before you purchase a car, you do a lot of preparation. You scour Web sites, read evaluations of specific makes and models by automotive experts and individual owners, check crash test ratings, take it for a test drive, even have your mechanic give it the once-over. Shopping for the best deal on auto insurance – and getting the right kind of insurance to meet your individual or family needs – requires an equal amount of diligence. Impulse buying can cost you money.

Purchasing auto insurance requires some advance work. Probably the first thing to do ahead of time is to check your credit report, There are three companies that provide this service for free: Equifax Credit Information Services; Experian and TransUnion Corp. This helps you identify and resolve any potential trouble spots that may drive up your insurance costs (and if you’re looking to buy a car, make it harder to get the best interest rate). This is different from your actual credit score (ranging from 300 to 850), which requires a small fee to obtain.

Bad credit can stop an insurer from issuing you a policy, or you might be offered a policy by a smaller insurer that is part of a larger group. Like with most factors, the cost varies depending on the insurer. Assuming your credit report is relatively clean, move to the next steps. One option for reducing your car insurance premium is to raise the deductible, or the amount you have to pay on repairs before the insurer makes any contributions. Just be aware that a higher deductible means more money out of your pocket if you make a claim. Deductibles vary by state, but are most often in amounts of $100, $250, $500 or $1,000.

Do you have a beginning driver in your family? Check into discounts that are available to soften the impact of insurance costs. For example: Is he or she a good student? Also, make sure the teenager completes a driver’s education course that includes behind-the-wheel experience.

If you’re in the market for a new car, consider how the type of vehicle would have an effect on insurance. A small, sporty model with a powerful engine may have a big “wow” factor, but in general, cars that cost more to repair cost more to insure than, say, a sturdy, less attractive four-door sedan. Some models may require a higher premium because they are more frequent targets of car thieves. Auto theft is covered under the comprehensive section of an auto insurance policy. Theft coverage applies to the loss of the vehicles as well as parts of the car such as air bags or music systems. For example, using 2009 models, a sports car such as a Dodge Viper would cost more than $2,000 annually to insure, but a van such as a Kia Sedona would come in at less than $1,000. A complete list appears here.

Comprehensive also covers accidents involving striking animals and weather-related losses. It differs from collision insurance, which generally covers you in collisions with other cars or property. If you own an older car, consider forgoing collision insurance, which covers the cost of repairing your car, or pays you fair-market value for your car if it’s totaled and you need a replacement. Accidents and tickets can (but don’t always) raise your rates; again, this varies by company and by state. If you get a ticket or are involved in an accident in another state, there’s a chance your insurance may not be affected. Also, insurers can drop clients after they have an accident.

Liability insurance covers you in the event your vehicle causes bodily injury and/or property damage. Companies also offer discounts for safe drivers (those who have gone a certain number of years without an accident). Your cautious, careful nature can pay off here.

Do you work from home, or perhaps ride to the office with a co-worker a few days a week? That’s another potential savings. For the most part, premiums are based on the projected amount of miles driven annually. If your “commute” involves simply walking to your computer, or you only drive to work one or two days a week, you can protect your money and the environment at the same time.