How do I get ringtones on my phone?

[Rikku]

I don't know much about ringtones and my phone or anything, but I really want a Final Fantasy or Kingdom Hearts ringtone. My phone does have bluetooth on it (though I don't know how to do it haha.....) so how do I get a ringtone? Do I like hit bluetooth and then open up the ringtone site or something? And how do you pay for it? Can you just bluetooth a song I already have from windows media player to it? Or do I have to find the song on a site and do it? Please explain how to get it!!!! Thanks!!!!