Coin

Currency is used in the world of Angry Birds to purchase various items.

In the games
Starting with Angry Birds Friends, players can accrue coins (or Bird Coins) in most games of the series. Bird Coins appear as small gold coins with Red's face on them. Some coins have different appearence in other games.

Angry Birds Friends
When you start the game for the first time after the release of the Bird Coins, you get a text box telling you about them, and you can also get  × 440, but only once. You can earn more for free by earning stars in Weekly Tournaments, and completing them. When you complete a Tournament Level, you will get +  × 2 for, + × 4 for , and +  × 8 for , if you get all the stars in a level, you will get +  × 14. You can also get from daily rewards. You will get + × 4 in the first day, +  × 6 in the second day in a row, +  × 10 in the third day in a row, +  × 16 in the fourth day in a row, and +  × 50 in the fifth day in a row. However, streak will be restart every five days if you login every day.

Angry Birds Star Wars (Facebook)
This section is in the need of expansion.

In this game, you can use coins to buy powerups, etc. to use in levels.

Angry Birds Star Wars 2
This section is in the need of expansion.

In this game, you can use coins to unlock characters, powerups, etc. to use in levels.

Angry Birds Go!
In Angry Birds Go!, Bird Coins appear in every track and can be collected to increase the amount of awarded coins when finishing a race.

In v1.0, they are mainly used to purchase upgrades for the player's karts, but once the player unlocks Rocky Road, they can also be used to purchase new karts as well.

In v2.0, they are mainly used to purchase upgrades for the player's karts with upgrade parts, and it's also used for purchase 3 upgrade parts at the shop (100 coins for regular parts, 1,000 coins for Rare parts, and 10,000 for Epic parts). There's a big coins appear in every track as well, for 50 coins.

Angry Birds Epic
This section is in the need of expansion.

Coins Are used to buy stuff at shop and buy potions and/or other items.

Angry Birds Stella
In Angry Birds Stella, the pigs can drop coins on the levels, you can get coins by earning the stars and roulette wheel after you pass the Bonus Levels.

They're mainly used to spend on the characters, and the Hammer power-up. You can also spend coins on investigate area to find the pigs on the map.

Angry Birds Transformers
This section is in the need of expansion.

Angry Birds POP!
This section is in the need of expansion.

Angry Birds Fight!
This section is in the need of expansion.

Angry Birds Rio
This section is in the need of expansion.

Coins are used to buy power ups and rio2 chapter 5

Bad Piggies
In Bad Piggies, the player earn coins by completing a level, get the Star Boxes (only in Sandbox), and feed the King Pig. The players can get coins by earning stars. Player get 1 coin for 1 star, 2 for 2 stars, and 3 for 3 stars.

Angry Birds Seasons
Coins were added on the Invasion of the Egg Snatchers update along with Bird Wear and Telebird. They are obtained after beating a level, watching ads or by purchasing it. They can be used to speed a Quest's time, buy episodes before Ham Dunk, Power-Ups or level-up Telebird or Shockwave Bomb, Star or Feather levels and could buy exclusive Bird Wear, but they were later made free.

Angry Birds
Bird Coins used to only appear in Angry Birds for Kakao. They used to purchase Power-Ups and Mighty Eagle. You can earn them by getting stars just for 10 coins. Coins were eventually added to every other region of Angry Birds. They are only used to buy power-ups. They can be purchased with Gems.

Angry Birds Action!
This section is in the need of expansion.

Angry Birds Ace Fighter
This section is in the need of expansion.

Angry Birds Goal!
This section is in the need of expansion.

Angry Birds Holiday
This section is in the need of expansion.

Angry Birds Blast!
This section is in the need of expansion.

In the films
In the Angry Birds animated films, Bird society and life appears to run on a currency system of sorts. In the days before the Great Egg War, Birds used primitive forms of currency that could be bartered for services. For instance, the Hug Trader in Bird Village charges one red berry for any additional hugs requested at his stand after his first complementary one. Throughout the war and beyond, the Birds adopted a more modern, but otherwise unknown currency system. During the Battle of Overseas Pranks, the last battle of the war, Hal was known to own a decent amount of money that he kept in a wallet. After being spurned by her lover Mighty Eagle and choosing to exile herself on Eagle Island, Zeta somehow raised a large amount of money to build her resort, and later a powerful superweapon that she intended to use to expand it through destructive conquest after being discontent with the resort's problems. She also penned a book titled Crazy Rich Avians, which perhaps explains how she got so rich.