I have an iphone5c and I want to get a ringtone without having to purchase one on itunes how do i do that??

I have an Iphone5c and I want to get ringtones without having to purchase them on itunes because I dont have a credit/debit card. I was told to download music on my computer and put it in itunes and then connect my iphone. I did that and I got the music in my phone but it's just under music and I'm still not able to use it as a ringtone. I was then told to download a ringtone make app and then I can do it that way. So I did that but on the instructions on how to load the ringtone to my computer and then back on to my phone the option that it says I should have itsn't there. Does anyone have anymore ideas??