Golden Pig Machine

The Golden Pig Machine is an item in Angry Birds Epic that the player gets after passing Level 3 of Golden Fields. It is used to roll for strong weapons and offhand items. The items' strength varies from 0 to 3 stars. Sometimes the items that you've already got are rerolled.

Cheap Roll
The Cheap Roll is worth 3 Lucky Coins. With it you have a normal chance of getting strong items. It fills up the Rainbow Bar (which we'll get to shortly) by 1/50, so you'd have to do 50 such rolls, which translates into spending 150 Lucky Coins, to completely fill it up.

Expensive Roll
The Expensive Roll is worth 20 Lucky Coins. With it you have a high chance of getting strong items. It fills up the Rainbow Bar by a fifth, meaning you'd have to spend 100 Lucky Coins to get the 5 rolls needed to completely fill it up. It makes sense to spend Lucky Coins on Expensive Rolls than on Cheap Rolls, but you can always choose which rolls to buy.

Rainbow Bar
The Rainbow Bar is a bar that's filled up when doing rolls. The player gets to roll a friend's Golden Pig Machine for free once per day, there's also an option to get a free roll by watching a video ad. The free rolls fill up the Rainbow Bar by as much as the Cheap Roll does. When rolling a friend's Golden Pig Machine, both the player and his/her friend's Rainbow Bars will be filled up. As soon as it's filled up, the player gets a 100% chance of getting a Legendary Set Item with the next roll.

Weapon Strength
Every time you roll, you will get about 0 to 3 stars - the more stars you get, the stronger the weapon is. You can get the same weapon, but it will get stronger based on the stars, if you get rainbow stars, you will get a legendary set item. The bird level is another factor that determines an item's strength, for example, a level 21 Paper (legendary set item) will be more powerful than the Paper that was acquired while being level 15, so it is advised to go for legendary set items when you have reached the maximum level.

Rainbow Riot
In v1.0.12 a period called Rainbow Riot was introduced. During it all your Golden Pig Machine rolls have a 3 times higher chance to get powerful items (that includes legendary set items). The Rainbow Riot starts when you have defeated the Day 7 Golden Pig (so don't forget to beat the Golden Pig every day) and it lasts for 15 minutes. Aside from higher chances, the Rainbow Riot is actually a great time for Cheap Rolls because the chances are that Cheap Rolls will give you more legendary set items than Expensive Rolls.

Legendary Set Items
Legendary Set Items are special weapons and off-hand items that give you a special bonus when equipped with their specific items like revive, extra damage, heal, etc... Each bird has 6 set items. Aside from giving a special bonus when equipped with their counterparts, the effects and chances of each legendary set item are 50-60% stronger/higher than those of plain items, for example, a plain item has a 15% chance to deal critical damage while a legendary set item has a 23% chance. Another example is that a plain item heals by 10% of dealt damage while a legendary set item heals by 15%. Note that these boosts don't apply to critical strikes and chain attacks, as in, a legendary set item's critical strike will still deal 50% bonus damage, not 75%, the same goes for chain attacks - 50% damage to an additional enemy, not 75%.

Red
Steel Force (23% chance to deal 50% bonus damage)

Steel Wall (reduces taken damage by 8%)

'''Steel Force + Steel Wall = Protector's Aura (all allies receive 10% less damage from attacks) '''

Titan's Wrath (8% chance to stun target for 1 turn)

Titangrip (increases attack power by 8%)

'''Titan's Wrath + Titangrip = Grand Slam (the hammer's stun effect lasts +1 turn) '''

Dragon Tooth (45% chance to attack an additional random enemy dealing 50% damage)

Dragon Scale (reduces taken damage by 8%)

'''Dragon Tooth + Dragon Scale = Dragon Breath (45% chance to deal 75% bonus damage to all targets)

'''

Chuck
Chronometer (increases attack power by 8%)

Chronos (heals by 15% of dealt damage)

Chronometer + Chronos = Time Jump (10% chance that Chuck receives a bonus turn after acting)

Phoenix Feather (30% chance to remove helpful effects from attacked enemies)

Phoenix Egg (increases maximum health by 23%)

Phoenix Feather + Phoenix Egg = Reborn (if Chuck is knocked out, he is instantly revived (once per battle))

Living Lightning (23% chance to deal 50% bonus damage)

Lightning Tome (increases maximum health by 23%)

Living Lightning + Lightning Tome = Twin Lightning (60% chance to deal 50% bonus damage to all targets)

Matilda
Yin (30% chance to remove helpful effects from attacked enemies)

Yang (reduces taken damage by 8%)

Yin + Yang = Perfect Balance (the Rage Chili fills up 20% faster)

Doom (8% chance to stun target for 1 turn)

Demise (increases attack power by 8%)

Doom + Demise = Nightmare (stunned pigs receive 200% damage at the beginning of their turn)

Honey Spoon (23% chance to deal 50% bonus damage)

Honey Jar (reduces taken damage by 8%)

'''Honey Spoon + Honey Jar = Sweet! (all friendly healing effects are 25% stronger)'''

Bomb
Golden Gun (23% chance to deal 50% bonus damage)

Golden Bullet (reduces taken damage by 8%)

Golden Gun + Golden Bullet = Pickpocket (30% chance to steal lots of Snoutlings from targets)

Rock (heals by 15% of dealt damage)

Paper (increases attack power by 8%)

Rock + Paper = Scissors (33% chance to deal 100% bonus damage to all targets)

Candy Bomb (45% chance to attack an additional random enemy dealing 50% damage)

Candy Chain (reduces taken damage by 8%)

Candy Bomb + Candy Chain = Sugar Rush (15% chance to heal all birds by 100% of the dealt damage)

The Blues
Ballista (23% chance to deal 50% bonus damage)

Ballista Bolts (increase attack power by 8%)

Ballista + Ballista Bolts = Artillery Strike (if the attack is a critical strike, the normal damage bonus is increased by an additional 100%)

The Sling (30% chance to remove helpful effects from attacked enemies)

Angry Birds Plushies (increases maximum health by 23%)

'''The Sling + Angry Birds Plushies = Save Me! (if the Blues are knocked out, they are instantly revived (once per battle))'''

RC Robot (45% chance to attack an additional random enemy dealing 50% damage)

Remote Control (increases attack power by 8%)

'''RC Robot + Remote Control = *BEEP* Attack! (45% chance to deal 75% bonus damage to all targets)'''

Trivia

 * The Candy Bomb (at first it was called Candy Crusher) is a reference to Candy Crush Saga as the ring is made from Candy Crush-shaped-candies.
 * The Candy Chain is a reference to candies in Candy Crush Saga.
 * The Dragon Tooth and the Dragon Scale are the same as the weapons of Sword Spirit, except when you put the Avenger helmet, Red will be alike to him.
 * You may watch a video for one cheap roll, but sometimes the glitch that you didn't watch a full video though you did occurs.
 * The "%" symbol is missing in some of the legendary set item descriptions (the in-game descriptions), for example, it says that Matilda's Nightmare set deals 200 damage to stunned enemies, but it's actually 200% of attack damage, so don't be fooled by the descriptions.