don't sweat it, we've all broken plenty of props I personally have been through at least $100 worth.
if you're near a major city, call some hobby shops you'll eventually find one that specializes in Quadcopter and Phantom parts... for example around Atlanta it took me 3 tries going to real hobby shops and having them look at me funny before I got referred to Atlanta Hobby, which turns out almost exclusively deals with quadcopters now and stocks tons of DJI hardware.
You can also find props on Amazon, but beware: normal retail price on propellers is $20/pair so if you see a deal that's too good to be true (like $10 for a pair or $20 for set of 4) beware, there are some listings where overseas retailers sell knockoff props listed as legit.