Lucky Egg is an item in the “Training” category (Items). It costs ₽10000.
In-game descriptions
| Ruby / Sapphire · Emerald | A hold item that boosts EXP. points earned in battle. |
|---|---|
| FireRed / LeafGreen | An item to be held by a POKéMON. An egg filled with happiness that earns extra EXP. points in battle. |
| Diamond / Pearl · Platinum · HeartGold / SoulSilver · Black / White · Black 2 / White 2 | An item to be held by a Pokémon. It is an egg filled with happiness that earns extra Exp. Points in battle. |
| X / Y · Sun / Moon · Ultra Sun / Ultra Moon | An item to be held by a Pokémon. It’s an egg filled with happiness that earns extra Exp. Points in battle. |
| Let’s Go, Pikachu! / Let’s Go, Eevee! · Sword / Shield | An item to be held by a Pokémon. It’s an egg filled with happiness that earns the holder extra Exp. Points in battle. |
Where to find it
Not placed on the atlas maps (so far: Red/Blue and Generation 3).
Held by wild Pokémon (Generation 3)
Common: 50% · rare: 5% (60% / 20% with Compound Eyes in the lead), from SetWildMonHeldItem.
| Rare |  Chansey  Blissey |
|---|
Sources : PokeAPI (items, item_flavor_text, machines) · atlas · pokeemerald species_info.h