Buying a first car?

Hello, I'd like to buy my own car. I've had my driver's license for a little over two years and am out of my probationary period. However, I've hardly driven it or had any insurance. I have two questions. How much will I pay on average for insurance, roughly speaking, and is 9 liters of petrol per 100km a lot? A third question: What kind of car would you recommend, or do you have any experience with what kind of car you would recommend (used).