This is a link from a Verizon answer today. It is loaded with mostly incorrect information. I responded with correct information in how to use Apple's software iTunes with what the person was trying to do [removal required by the Verizon Wireless Terms of Service] . I've participated in Apple's own forum since 1998 and have never seen that done. Apparently Verizon will intentionally force incorrect information on customers rather than easily acknowledge a error or mistake. So I don't think I can provide you proper info, good luck.
You can use iTunes to create your own ringtones with music that you either purchased from iTunes or that you imported into iTunes. The info on that link is only partially correct (yes you can purchase ringtones on iTunes) but it's not the only way to create ringtones. If you do an Internet search you will find numerous tutorials on how to do it. If the correct answer was already deleted it might be your best method of finding the info yourself. I know I have posted info on how to do it on here in the past but that was so long ago I couldn't direct you to the threads where I listed details. It's not difficult at all but it's easier for you to follow step by step tutorials when you're first learning how to do it.
Norman1952, the easiest way would be to purchase ringtones from Apple. But to create them yourself would be more enjoyable, and actually fun to do. This link has great instructions on how it's done but may take a little practice. It is very informative because there are a few steps that are easy to miss, like create ACC version which is hidden in iTune preferences, changing extension from M4a to M4r, etc.etc.
If the video doesn't play after the ad you'll need to click on the button on the left twice. It mentions iTunes 10 but will work the same with itunes current version 12.