I touched a car bumper when i was backing, how much that would affect my insurance?

I would like methods for reducing expense of auto  insurance      plz?
"Our room-mate only got two seats. One for changing lanes for not having his headlights on at 9 o'clock through the night without the need for a blinker and another. He had simply quit a parking lot. He had a prior admission for planning 12 on the speedlimit that was shifted to some parking abuse