Cheapest priced copy (Gatecrash): $0.35 at Card Kingdom, near mint, their price list as of .
Psychic Strike 
Instant · Common · Gatecrash · #189
Counter target spell. Its controller mills two cards.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Gatecrash | 189 | Common | $0.35 | $0.99 |
2 rulings from Wizards of the Coast
- 24 January 2013You may target a spell that can’t be countered. When Psychic Strike resolves, the target spell will be unaffected, but its controller will still put the top two cards of their library into their graveyard.
- 24 January 2013If the target spell is an illegal target when Psychic Strike tries to resolve, Psychic Strike won’t resolve and none of its effects will happen. The target’s controller won’t put any cards from the top of their library into their graveyard.