I cracked my iPhone 4 screen?

It flew and then it fell on its back and I had a really bad case on it that doesn't protect anything and it fell on the back and the front cracked. It's pretty bad and it looks awful. I got it two weeks ago because it was my dads friends and he didn't want it so be gave it to me. So I transferred my old phone to the iPhone, and then this happened. I obviously don't have a warranty but since the iPhone 4 is $0 with contract could I get another one from the Apple Store for free!

It seems possible but i have never try, if you just crack the screen, replace one screen is also ok within 10 dollars.