Cheapest priced copy (Double Masters 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Battlefield Promotion 
Instant · Common · Jumpstart · #91
Put a +1/+1 counter on target creature. That creature gains first strike until end of turn. You gain 2 life. (A creature with first strike deals combat damage before creatures without first strike.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 7 | Common | $0.35 | $0.49 |
| Foundations Jumpstart | 173 | Common | $0.35 | — |
| Jumpstart | 91 | Common | $0.35 | — |
| War of the Spark | 5 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 3 May 2019If the target creature is an illegal target by the time Battlefield Promotion tries to resolve, the spell doesn't resolve. You don't gain 2 life.