Whats the best insurance that a teenager could get?

I am 18 years old and I just got my license. I just got a 03 Toyota Corolla. Every insurance company I go is telling me I had to pay around $300 a month. I need to find an insurance company that can give me a lower quote. I know it still going to be expensive but I am looking to see if I can get a payment of at leas around $150 a month.