The cost of a screen replacement is dependent on which model of iPhone has been damaged. It also depends on if the owner has insurance or a warranty.
To replace the screen of an iPhone 6, the cost is $109 as of 2015. The cost of replacing it on an iPhone 5 or iPhone 6 plus is $129. Apple will also charge for fixing any other damage to the phone. These additional charges will be added to the customer's credit card. If AppleCare + was purchased, it is $79 to have the screen replaced. The insurance only covers the cost of replacing the screen twice.