The ability affects each spell that's not a creature spell, including your own. Creature spells with another type, such as artifact creature spells, aren't affected.

To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases (such as that of Vryn Wingmare), then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.