Progressive wants you to. Progressive has recently made it into the top 5 of Information Week's list of the country's most innovative users of business technology. One reson they got into the top 5 is their "Name Your Own Car Insurance Price" tool.
It is a really neat tool. You put in info about you and your car into Progressive's tool on their website and Progressive will give the user car insruance options as close to the clients suggested price. Users can also drag a sliding bar to tweak their coverage to get even closer to the price they want.
One thing to remember is that only looking at the price of car insurance is a bad idea. The whole car insurance package needs to properly meet your needs. Of course paying a cheap car insurance price is no good if it does not cover you well.
Evaluating insurance on price is the first step in a bad process for buying insurance. Cost of insurance is normally inversely related to the quality of coverage (the higher the price- the better the coverage). That said, there are insurance companies who have better rates in certain geographic locations or based on your demographic or some other factors.
Best way to buy insurance is to start with a trusted advisor. Allow them to review your life circumstances and recommend coverage from there. Then, you can make your purchase decision based upon your risk tolerance and your budget.