Cheapest priced copy (Modern Horizons): $0.35 at Card Kingdom, near mint, their price list as of .
Savage Swipe 
Sorcery · Common · Modern Horizons · #178
Target creature you control gets +2/+2 until end of turn if its power is 2. Then it fights target creature you don't control. (Each deals damage equal to its power to the other.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons | 178 | Common | $0.35 | $0.99 |
4 rulings from Wizards of the Coast
- 14 June 2019The target creature you control gets +2/+2 only if its power is exactly 2 as Savage Swipe resolves. It’ll still fight if it doesn’t get +2/+2.
- 14 June 2019You can’t cast Savage Swipe unless you choose both a creature you control and a creature you don’t control as targets.
- 14 June 2019If the creature you control is an illegal target as Savage Swipe tries to resolve, no creature gets +2/+2. If that creature is a legal target but the creature you don’t control isn’t, it still gets +2/+2 until end of turn if its power is 2.
- 14 June 2019If either target is an illegal target as Savage Swipe tries to resolve, neither creature will deal or be dealt damage.