The Aetherspark 231/291 (Aetherdrift)

As long as The Aetherspark is attached to a creature, The Aetherspark can't be attacked and has "Whenever equipped creature deals combat damage during your turn, put that many loyalty counters on The Aetherspark." +1: Attach The Aetherspark to up to one target creature you control. Put a +1/+1 counter on that creature. −5: Draw two cards. −10: Add ten mana of any one color.

NM - $34.20
LP - $27.40
MP - $20.50
HP - $13.70
DMG - $6.90