Q: how to make your own ringtone free

hello

I want to make my own ringtone from my music. I have read many ways on how to make it happen such as:

1-iTunes: select the duration and then make a copy of it then convert it to M4r, but it did not work .

2- use garage band but the program not free.

3-use websites to convert it but it did not work.

the song is Arabic and unfortunately, I did not found it in the store.

I would appreciate if anyone can help me to change it.

thanks