Balloon Berry changes how its holder pays to retreat. The original Neo Revelation wording discarded Balloon Berry in place of the Energy cards normally discarded on retreat, while the Deoxys wording rewrote this so the holder's Retreat Cost becomes 0 outright as long as the card is attached, discarding it only when the Pokémon actually retreats.
Balloon Berry debuted in the WOTC era's Neo Revelation with art by Keiji Kinebuchi, then was reprinted in the EX era's Dragon and again in Deoxys, both again credited to Kinebuchi. The Dragon wording added a clause discarding the card if the holder is Knocked Out. The Deoxys printing tweaked the effect text to reflect an errata issued before that expansion's release. Our catalog lists 3 printings.
Balloon Berry was also reprinted in the Japanese Flygon and Salamence Constructed Starter Decks, and Bulbapedia files it among Trainer cards that change a player's Retreat Cost.
The Neo Revelation printing is Balloon Berry's first release
The Dragon printing is again credited to Kinebuchi and adds the Knocked Out discard clause
The Deoxys printing reflects the errata with the Retreat Cost 0 wording
It changed the effect from discarding the card instead of Energy on retreat to setting the holder's Retreat Cost to 0 while attached.
Keiji Kinebuchi illustrated all three printings.
From Neo Revelation (2001) · 1 printing
Attach Balloon Berry to 1 of your Pokémon that doesn't have a Pokémon Tool attached to it. When the Pokémon Balloon Berry is attached to retreats, discard Balloon Berry instead of discarding Energy cards.
From Dragon (2003) · 1 printing
Attach Balloon Berry to 1 of your Pokémon that doesn't already have a Pokémon Tool attached to it. If that Pokémon is Knocked Out, discard this card. When the Pokémon Balloon Berry is attached to retreats, discard Balloon Berry instead of discarding Energy cards.
From Deoxys (2005) · 1 printing
Attach Balloon Berry to 1 of your Pokémon that doesn't already have a Pokémon Tool attached to it. If that Pokémon is Knocked Out, discard this card. As long as Balloon Berry is attached to a Pokémon, that Pokémon's Retreat Cost is 0. When this Pokémon retreats, discard Balloon Berry.

Balloon Berry
Pokémon Tool
First printed in Neo Revelation (2001)
Attach Balloon Berry to 1 of your Pokémon that doesn't already have a Pokémon Tool attached to it. If that Pokémon is Knocked Out, discard this card. As long as Balloon Berry is attached to a Pokémon, that Pokémon's Retreat Cost is 0. When this Pokémon retreats, discard Balloon Berry.