Window shopping's a great way to find affordable car insurance. Figure out which coverages you want beforehand. Then make sure each quote includes the same coverages and limits. This'll give you a better apples to apples comparison.
You could also lower insurance costs by reducing your coverage limits and increasing your deductibles. Just know that a higher deductible typically means you pay more out of pocket for a claim.
Also, say your auto policy only satisfies your state's minimum liability requirements. Your car insurance in this case might be on the cheap side. But it wouldn't account for collision damage to your car. Nor would it step in if your ride was ever vandalized. Your wallet would be feeling it and we don't want that.
In other words, "cheap" doesn't always translate to the "best" car insurance.