Hallowed Fountain is a rare Land — Plains Island card from Lorwyn Eclipsed Promos (PECL), collector number 265p. Current market price: $7.89 (foil $8.83), TCGplayer market prices via Scryfall.
({T}: Add {W} or {U}.) As this land enters, you may pay 2 life. If you don't, it enters tapped.