How much would be my insurance with this car?

I have a buddy who has an extra car. He let the car is driven by me. He's a liability-coverage around the automobile and I do not have any motor insurance before. Can it be okay to travel? Liability insurance comes with individuals or automobiles?
Where am I able to buy inexpensive dental insurance that's effective quickly?
Will be the Smart Fortwo vehicle's insurance cheaper?
"While traveling for function /rental a car from Avis for approximately a few months I am going to be letting. Will my present car  insurance     be enough or can I take out a separate policy to the rental car itself? I truly cannot afford to consider the insurance so Iam trying to find the following best option that will preserve me well protected ontheroad