Cheapest priced copy (Khans of Tarkir): $0.49 at Card Kingdom, near mint, their price list as of .
Trap Essence 
Instant · Rare · Khans of Tarkir · #209
Counter target creature spell. Put two +1/+1 counters on up to one target creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.49 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Khans of Tarkir | 209 | Rare | $0.49 | $0.49 |
| Khans of Tarkir Promos | 209s | Rare | — | $1.99 |
One ruling from Wizards of the Coast
- 20 September 2014You don’t have to target a creature to cast Trap Essence, although you must target a creature spell on the stack.