"You ask the Wild Magic to do something - heal someone, find a lost object, change the weather, many other sorts of things. The energy to do it usually comes from yourself, the people around you, or objects where you've stored energy that ultimately came from those places, but once in a very long while the Wild Magic will power a spell itself. And apart from that immediate cost, every spell of the Wild Magic also comes with a Mageprice, which is like your friend asking you for a favour in return."