The Earth Crystal

If two or more effects attempt to modify how many counters would be put onto a creature you control, you choose the order to apply those effects, no matter who controls the sources of those effects.

The cost reduction applies only to generic mana in the total cost of green spells you cast.

You choose how many targets The Earth Crystal's last ability has and how the counters are distributed as you activate it. Each target must receive at least one counter. This means, for example, that you can't target two creatures and assign them two and zero counters respectively.