It can vary widely but the cost of a door ding depends on the size and the nature of the damage to the door. If the ding is small enough to be fixed with a few finishing touches, then it should only cost about $100.
The first step is to make sure the car is off and the windows are rolled up. The next step is to run a heavy towel along the edge of the windshield where it’s cracked. This is to remove any debris that might be causing the crack. The next step is to use a clean towel to gently smooth the crack.