Brass's Bounty is a rare Sorcery card from Rivals of Ixalan Promos (PRIX), collector number 94p. Current market price: $3.62 (foil $2.16), TCGplayer market prices via Scryfall.
For each land you control, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")