Ringtones can say a lot about you, your personality, style, and your attitude. And they can be very helpful to let you know exactly who is calling. But iPhone is limited in terms of ringtones for some reason. You may only use either the small default ringtones that comes with the phone or purchase from the iTunes store for 99 cents each. Anyway, for ringtone variety, creating ringtones for your iPhone in iTunes is a super expensive way to go.
For Mac users, iPhone Ringtone Maker Mac can help you make custom free iPhone ringtones from any song or video you like in only 4 easy steps.
Step1: Launch iPhone Ringtone Maker for Mac and Connect Your iPhone
Step2: Import a Song or Video
You can either choose a song /video in iTunes library or directly drag one from your computer.
Step3: Trim the Audio/Video File to Start Making
Use the blue slide bar to trim the file you import. You can also set the length of the ringtone by typing the exact time value into the time-setting boxes.

The program also allows you to add Fade in/out (up to 5 seconds)effect and pre-listen to the ringtone you made.
Step4: Export Ringtone to Your iPhone
Select "Transfer to iPhone" and click "Start", the ringtone made will be transferred to both your iPhone and iTunes. Click "Start" alone, the Ringtone will then be in iTunes.
You can now let your iPhone sing your song.
P.S. Ringtone Manager
iPhone Rigntone Maker Mac has a Ringtone Manager which is designed to help users to manage their ringtones more conveniently with out using iTunes. You can now not only transfer them between iTunes and iPhone freely but also delete or pre-listen to them. For those who have problem syncing ringtones, Ringtone Manager can also help you solve this problem.
Tags: Create iPhone Ringtone, Make iPhone Ringtone on Mac