Doran, Besieged by Time 334 (Lorwyn Eclipsed)

Each creature spell you cast with toughness greater than its power costs {1} less to cast. Whenever a creature you control attacks or blocks, it gets +X/+X until end of turn, where X is the difference between its power and toughness.

NM - $3.70
LP - $3.00
MP - $2.30
HP - $1.50
DMG - $1.50