Planar Chaos 97 (The List Reprints)

At the beginning of your upkeep, flip a coin. If you lose the flip, sacrifice this enchantment. Whenever a player casts a spell, that player flips a coin. If they lose the flip, counter that spell.

NM - $12.40
LP - $10.00
MP - $7.50
HP - $5.00
DMG - $2.50