I've repaired six or seven iphone screens. it's honestly one of the hardest phones to work on that I've ever come across, but it's definitely doable if you are somewhat electronically savvy. if your LCD isn't cracked, and it's just the front glass that is damaged, then it will cost you about 10 bucks for replacement glass off of amazon.
there are plenty of instructional videos on youtube that will walk you through the process. it's not too bad, but it's not as easy as a lot of other phones that I've repaired.