By using iTunes to modify songs in your music library, you'll never need to pay for another ringtone again. Ringtones should be no longer than 30 seconds in length, so most songs will need to be edited before they can be used as a ringtone. To do this, you will need to use only unrestricted songs. Some music files use restricted digital rights management (DRM) coding, which prevents you from copying and modifying the song.
Open iTunes on your computer.
Select a song that is not restricted by digital rights management (DRM).
Listen to the song and select 30 seconds of it that you would like for to use for your ringtone. Note the beginning and end time of that section by watching the time counter at the top of your iTunes window.
Right-click on the song in iTunes and click on "Get Info." A pop-up window will appear. Click on the "Options" tab.
Enter the "Start Time" for your new ringtone in minutes and seconds. Then enter the "Stop Time." Click on "OK."
Right-click your song in iTunes. Then click on "Convert Selection to AAC." After a few seconds, iTunes will create a copy of the song in AAC format. This will be your new ringtone.
Right-click on the new copy of the song and then click on "Delete." Then click on "Keep Files." This will remove the ringtone from iTunes without deleting it from your computer.
Locate the ringtone file in your User folder. It is usually located in the folder with the name of the band under "Music > iTunes > iTunes Music."
Look at the name of the file. It should have an extension of ".m4a." If you cannot see the extension, click "Organize" in Windows 7, and click on the "View" tab. In other versions of Windows, go to the Start button on your desktop; select "Control Panel" > "Appearances and Personalization" > "Folder Options" > "View" > "Advanced Settings." Uncheck the box next to "Hide extensions for known file types." Click "OK."
Click on the name of the file to highlight it, then wait one second and click on the name again. This will allow you to edit the name of the file.
Change the extension of the file from ".m4a" to ".m4r." A pop-up will appear warning you that you are changing the file name. Confirm your decision by clicking "OK."
Connect your iPhone to to your computer. Synchronize your iPhone to iTunes. After the synchronization, your new ringtone will be copied to your iPhone.