Starlit Sanctum is a uncommon Land card from Onslaught (ONS), collector number 325. Current market price: $0.44 (foil $26.45), TCGplayer market prices via Scryfall.
{T}: Add {C}. {W}, {T}, Sacrifice a Cleric creature: You gain life equal to the sacrificed creature's toughness. {B}, {T}, Sacrifice a Cleric creature: Target player loses life equal to the sacrificed creature's power.