Magic roots, common, 3/3/3
Nature
Stock: +N
N=#Nature in hand
Maybe it's a good idea. But then Beast, Soldier, Alliance, Aqua, Illusion etc. should have their own self-paying stock increasers.
In fact, Nature doesn't need a card like this because of Lake fairy, Deathwood necromancer, Deathwood shaman and Ancient sage. Only Undead has more effective stock increasers or self-paying cards.