Past in Flames is a mythic Sorcery card from Signature Spellbook: Chandra (SS3), collector number 4. Current market price: $2.90 (foil $4.67), TCGplayer market prices via Scryfall.
Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)