Cheapest priced copy (March of the Machine): $0.35 at Card Kingdom, near mint, their price list as of .
Angelic Intervention 
Instant · Common · March of the Machine · #5
Target creature or planeswalker you control gains protection from colorless or from the color of your choice until end of turn. If it's a creature, put a +1/+1 counter on it. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything with that quality.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine | 5 | Common | $0.35 | $0.79 |