The cost to fix an iphone screen at a local cellphone repair shop will probably be about $75 to $125 dollars.
Based on what online fix shops are quoting for screen replacement jobs,
this price appears to be the average.
Take note however,
that if you get the LCD screen fixed at somewhere other than Apple,
you will likely void your warranty.
Apple requires also that you use only genuine Apple branded parts and that the service be done by an authorized dealer if you want to save your limited warranty.