European Expressions' Music Maker is a great started instrument for children 3 and up. A variation on the Greek Zither, cousin to the American Autoharp, the Music Maker is a simple stringed instrument where each string is its own note (no need to make chords.)
And don't forget to pick up some Music Sheets! No music reading needed, simply slide the sheet into your Music Maker and simply follow the dots! Dot markers show you what notes to play and in what order. One of the easiest ways to learn to play an instrument.