Cheapest priced copy (Guilds of Ravnica): $0.49 at Card Kingdom, near mint, their price list as of .
Ionize 
Instant · Rare · Guilds of Ravnica Promos · #179p
Counter target spell. Ionize deals 2 damage to that spell's controller.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Guilds of Ravnica | 179 | Rare | $0.49 | $1.99 |
| Breaking News | 49 | Rare | $0.49 | $0.49 |
| Guilds of Ravnica Promos | 179p | Rare | $0.59 | $1.49 |
| Guilds of Ravnica Promos | 179s | Rare | — | $1.99 |
One ruling from Wizards of the Coast
- 5 October 2018A spell that can’t be countered is a legal target for Ionize. The spell won’t be countered when Ionize resolves, but Ionize still deals 2 damage to that spell’s controller.