1. Go to your Facebook Wall
2. Create a status update that says "I want to win"
3. Before you click post, click the little button that looks like a pin
4. Type Walgreens and choose a Walgreens location from the list
5. After choosing a Walgreens location, click post
If you are using the Facebook mobile app, just choose Places, then Check In, find a Walgreens, add "I want to win" to your update and click post.