Curse of Opulence is a uncommon Enchantment — Aura Curse card from The List (PLST), collector number C17-24. Current market price: $5.17, TCGplayer market prices via Scryfall.
Enchant player Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this token: Add one mana of any color.")