Here's how you can download the official Facebook app free for Android.
1. Go to the Google Play page for the free app Facebook.
2. Tap the Install button.
Here's a description of Facebook:
"Keeping up with friends is faster than ever.
• See what friends are up to
• Share updates, photos and videos
• Get notified when friends like and comment on your posts
• Text, chat and have group conversations
• Play games and use your favorite apps"