Struggle To Sruvive

Each creature spell has "As an additional cost to cast this spell, sacrifice a creature. This creature enters the battlefield with X +1/+1 counters where X was the sacrificed creatures power."
Whenever you sacrifice a creature you may pay 3 life, if you do add {b}{b}{b} to your mana pool, then return another target creature with lesser mana value from the graveyard to your hand.