Creative Commons works with copyright to help protect the things that you create. Having a license makes the idea yours, so nobody else can have it. Creative Commons is also free, which is even better.
I have never used someone else's work without giving credit to the original creator. I have used the internet for projects but I've always included a list of the works cited. You can get in big trouble if you don't give credit to the original creator, not just in school but with the law.

If I found out someone was using my work and making a profit from it I would be really angry. It isn't fair if I created something first and someone else got the credit for it. It's pretty much like stealing. It's wrong and illegal.