Ajani's Mantra is a common Enchantment card from Duel Decks: Ajani vs. Nicol Bolas (DDH), collector number 22. Current market price: $0.37, TCGplayer market prices via Scryfall.
At the beginning of your upkeep, you may gain 1 life.
All Duel Decks: Ajani vs. Nicol Bolas cards and prices