The Master Ball card from the Base Expansion Pack set in Pokémon is categorized as an Uncommon rarity. Currently valued at $12.99, it holds significance for collectors due to its strategic gameplay utility, allowing players to catch any Pokémon without fail. As part of the original set, it appeals to both competitive players and nostalgic fans, contributing to its steady demand in the market. Graded versions can command higher prices, reflecting its desirability among enthusiasts.