You have discovered how to perform your magic rituals with fewer alchemical reagents than other magicians require.

Daily
Free Action      Personal

Trigger: You are performing an Arcana ritual of one-half your level or lower

Effect: You expend only half of the ritual's gold piece component cost (any focus item must still meet the minimum cost), although you cannot use this power to reduce the component cost of the rituals Brew Potion and Enchant Magic Item. If you make an Arcana check as part of the ritual and dislike the result, you can reroll the check with a +4 power bonus and use either result.

Published in Player's Handbook 3, page(s) 165.