Arena of Glory 215 (Modern Horizons 3)

This land enters tapped unless you control a Mountain. {T}: Add {R}. {R}, {T}, Exert this land: Add {R}{R}. If that mana is spent on a creature spell, it gains haste until end of turn. (An exerted permanent won't untap during your next untap step.)

NM - $16.00
LP - $13.00
MP - $9.50
HP - $6.50
DMG - $3.50