Ringtone Question

I have an IPhone 4. I wanted a custom ringtone so I went to settings/sounds/ringtones and to the ringtone store. I purchased the song I wanted and I expected it to appear in my ringtone list so I could use it, but it did not. I cannot make it my ringtone. Can someone tell me how to do this? Also, if it cannot be done can someone tell me where I can download college fight songs and use them as my ringtone. There are a lot of sites that have them but they are scams.

Thanks.