Musical cards are a fun way to enhance the thoughtfulness or humor of a greeting card. Most feature a small device imbedded in the card, which plays music when the card is opened and is powered by a tiny battery. Types of music can vary greatly, and may include birthday songs, Christmas tunes or other popular themes like those from the Star Wars films. Unlike the standard greeting card, expect musical cards to be three to four times more expensive, but they may be worth it in the smiles and happiness they can produce.