Cheapest priced copy (Eternal Masters): $0.35 at Card Kingdom, near mint, their price list as of .
Second Thoughts 
Instant · Common · Eternal Masters · #27
Exile target attacking creature.
Draw a card.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
2 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Eternal Masters | 27 | Common | $0.35 | $0.49 |
| Odyssey | 45 | Common | $0.35 | $0.79 |
One ruling from Wizards of the Coast
- 8 June 2016If the targeted creature is an illegal target when Second Thoughts tries to resolve, the entire spell doesn’t resolve. You won’t draw a card.