How would i get free ring tones (without internet from my phone) to my phone?

I have a Samsung SPH-M500 phone with Sprint service. Now in order to get a ring tone I have to use to provided internet service with sprint, but my internet privileges on my phone is limited. So I was wondering is there a way to get ring tones using my micro SD card, and if so under what folder or file? How could I save it to my phone and use them as ringtones? Please help!!!!!!!!!!!!!!!!!!!! Thanks XD