Sudden Breakthrough is a common Instant card from Strixhaven: School of Mages (STX), collector number 116. Current market price: $0.22 (foil $0.50), TCGplayer market prices via Scryfall.
Target creature gets +2/+0 and gains first strike until end of turn. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")