When you register your Starbucks card, any gift card you received, keep reloading that card to earn stars (points). At 5 stars (Green level) you get free refills while you are in the store, free syrup or soy milk, free tall drink when you buy a pound of coffee. Earn 30 stars in one year, you are Gold Level and get even more.
You earn one star per purchase. Totally worth it if you go to Starbucks alot, the points add up fast! It is worth it to buy a card & register.