Like most Magic: The Gathering cards, the value of Teferi, Mage of Zhalfir depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy: Through the Ages)
This turns off common red removal like Torch the Tower and Pyroclasm
While this definition is what most Magic: The Gathering (MTG) players will default to when asked what they consider a tutor, Id argue the concept has become a bit broader than that since the 1990s
While Prismatic Evolutions did include other great hits like the Roaring Moon ex and Bloodmoon Ursaluna ex, this Eevee-centric set was incredibly difficult to get your hands on early in the year with incredibly harsh pull rates
Their value depends on demand, rarity, and condition compared with English versions
Additionally, this drop is available in Japanese as well as English, for the same price