I have a COD5/social problem...?

I just borrowed COD5 from a friend 2 days ago. while playing, i got up to go get pretzels and tripped over a wire that pulled my 360 from vertical to horizontal. Consequently, the disk got all scratched up and the 360 doesn't even realize there's a disk. my friend won't take this lightly and i don't have a lot of money. Any cheap ways to fix the disk?