what state are you in, try that states equivalent.
apart from just looking at the cheapest, consider the excess and coverage too.
cheaper premium, usually means a higher excess. Fine if you just want cover for major damage, and always make sure you are clear on what will be covered.
eg, if someone steals my wheels or my stereo i have an agreed value of replacement.
There are so many variables that determine which will be best for you, just work out exactly what you want vs what you are prepared to pay and find the closest match. Every company will have good and bad reviews.