Kaza, Roil Chaser 225 (Zendikar Rising)

Flying, haste {T}: The next instant or sorcery spell you cast this turn costs {X} less to cast, where X is the number of Wizards you control as this ability resolves.

NM - $1.50
LP - $1.50
MP - $1.50
HP - $1.50
DMG - $1.50