When you are on the home screen, select the music player and then go to the all tab. Once you are there, pick a specific music file (such as the free samsung vibrant mp3 ringtone you just downloaded). It will begin to play the music, but after that you can click the “set as” button and it will allow you to set the song as your general ringtone, or as a specific ringtone for a specific contact (or for a group of contacts). You will also find other options here that allow you to share the music.
So, in order to play free ring tones on the Samsung vibrant, simply transfer the mp3 file to your phone and follow the directions above! There are also tons of sites that offer free ringtone downloads, you can go ahead and start gathering up downloads for some of your favorite songs, artists, and music styles today.