Cheapest priced copy (Scars of Mirrodin): $0.35 at Card Kingdom, near mint, their price list as of .
Seize the Initiative 
Instant · Common · Scars of Mirrodin · #20
Target creature gets +1/+1 and gains first strike until end of turn.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Scars of Mirrodin | 20 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 January 2011A creature that gains first strike after other creatures with first strike or double strike deal combat damage in the first combat damage step will still deal damage in the second combat damage step.