2,250 g
This item page for Innervating Locket reflects public Arena Mayhem data for patch 26.19.
Unique - Fill the Soul:
Gain a charge each time you or champions within 800 units cast an ability, up to 30. At maximum charges, gain 100 – 250 (based on level) ability power and 15% – 25% (based on level) bonus movement speed for the rest of the round, as well as a 400 – 750 (based on level) shield that lasts until destroyed. Charges are reset every round and between each phase in a round.