A thread asking this exact same question was made just a little while ago... at least reading the top 10 threads before posting would help...
https://forums.macrumors.com/threads/508598/
Are there any good sites out there that offer free mp3 ringtones that can easily be opened in Garage Band and imported as a ringtone in iTunes? Thanks.
Or are you asking for sites that have free music downloads? I believe that is a violation of the forum rules.
That's exactly what I'm doing. Mods, by all means, delete.
Can't you open any mp3 file in Garage Band and CREATE your own ringtone?
I have tried this and I can't figure it out. Is it any music file or song I have in iTunes?
GarageBand, not iTunes. Make a new music project in GarageBand, import the audio of your choice (in this case an MP3) in a new track, edit it however you want, then from the Share menu, choose "Send Ringtone to iTunes"