Mercy... you can make a ringtone from any song/sound clip in existence and use it for a ringtone. free. All that is required is the usb->phone connection and some free software.
What I do is:
Run Audacity in the background, recording sounds played through my computer while playing the track via itunes. Next I trim the track to length (30sec is normally fine) fade in, fade out, and amplify until the waves reach near the top of the graph (any more and you will get distortion). Run BitPim and put the clips in your ringtones/sounds directory.
I have never bought a ringtone yet.