in yugioh what is a side deck Top 10 Cards Goat Format Side Deck basics - Yugipedia

If you add the components (deck box, coins, dice), then there are a few sold listings in the $15 range

Righteous Avengers Rarity: Common TYPE: Creature SUBTYPE: Human Soldier CMC: 5 Mana cost: USD: $1.72 EUR: 1.97 TIX: 0.00 EDHREC RANK: 31239 (3/1) Plainswalk (This creature can't be blocked as long as defending player controls a Plains.) Ring of Immortals Rarity: Rare TYPE: Artifact SUBTYPE: - CMC: 5 Mana cost: USD: $28.84 EUR: 25.64 TIX: 0.00 EDHREC RANK: 26112 , : Counter target instant or Aura spell that targets a permanent you control

Turn 3 : During your untap step before you untap, Old Fogey phases in

It's two keywords: "Dungeon" for the new card type, and "Venture" for how we interact with them (which remains a mystery)