Welcome! The more cards you have, the more players can play (against the Evil Deck), each person can bring their own deck to the table (Rules allow for up to 4 copies of each card per deck). The 259 card Full Set gets you all the cards (dividing the cards could allow up to 4-5 players), while the other packs have pre-constructed decks that might be helpful for beginners. You may always add or change your decks and buy more cards later to empower your decks. Thank you for your business and to Christ be the glory in all things including game-making and game-playing.