Skill groups representing the schools of magic cost the same as any other Skill Group. 5/lvl.
Spells are like skills 1/lvl.

I had this on a spreadsheet to get the numbers right. The wind spell that was purchased without the Wind Skill Group costs 3 CP. It should say:

Wind Spell - Invisibility +3 TN 15 Cost 2

Forgot to say that he has 65 Mana.
My warrior example from an earlier post was wrong, he should have 18 Mana, not six.
Formula for Mana is (ENR + DIS) * 3

The spellcaster has 65 because of the Elemental Power Trait.

The bonus is +2 to the multiplier for spellcasters, making his (ENR + DIS) * (3 + 2)
The trait also provides a bonus to spells that attempt to increase damage/range/area of effect. More on that later.
NOTE: The determination of 65 mana may change. On further review it seems extreme.

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