As Foretold is a mythic Enchantment card from Amonkhet (AKH), collector number 42. Current market price: $1.48 (foil $3.72), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, put a time counter on this enchantment. Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on this enchantment.