Cheapest priced copy (Modern Horizons 2): $0.49 at Card Kingdom, near mint, their price list as of .
Void Mirror 
Artifact · Rare · Modern Horizons 2 · #473
Whenever a player casts a spell, if no colored mana was spent to cast it, counter that spell.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $0.49 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 | 242 | Rare | $0.49 | $0.99 |
| Modern Horizons 2 | 435 | Rare | $1.79 | $0.99 |
| Modern Horizons 2 | 473 | Rare | $0.49 | $1.99 |
| Modern Horizons 2 Promos | 242s | Rare | — | $0.79 |