Chances are, they're gonna be dodgy. Like, seriously dodgy. I highly doubt that you'll find any free websites (by free I mean completely free)
Maybe just google what type of music files are compatible with your phone and connect it up to the compuer and put on some songs manually. Better than ending up haing to pay heaps of money for a supposedly free website.
This website is FREE but it is by uploading music off of your computer music library like itunes or windows media player. You upload your song then you choose what part of the song you would like to be as your ringer or call tone ect. myxer dot com.