Your Studio G Plus HD features a microSD memory card reader. If your personal computer can also read that type of card (Most laptops are so-equipped), you should be able to save a music file
The BLU Studio G Plus HD is an Android phone and there are plenty of free ringtone apps such as MP3 Cutter, RingDroid (open source) and more.
Here are some of the free ringtones (BLU Studio G Plus HD-compatible) offered here at MartinsRingtones.com:
Free Horror MIDI Ringtones Free Ghost Ringtones Free Ringtones-a-gogo Free Techno Ringtones Listen To All Our Free Polyphonic Ringtones