Courier's Briefcase is a uncommon Artifact — Treasure card from Streets of New Capenna (SNC), collector number 142. Current market price: $0.27 (foil $0.11), TCGplayer market prices via Scryfall.
When this artifact enters, create a 1/1 green and white Citizen creature token. {T}, Sacrifice this artifact: Add one mana of any color. {W}{U}{B}{R}{G}, {T}, Sacrifice this artifact: Draw three cards.