Barbara, Voice of Favonius

Lifelink.
At the beginning of your upkeep, you gain 4 life.
Whenever you gain life each turn, you may pay
{w}{w}. If you do, you may return target creature
card with mana value X or less from your
graveyard to the battlefield, where X is the
amount of life you gained. You may do this
only once each turn.