Cheapest priced copy (Amonkhet): $0.35 at Card Kingdom, near mint, their price list as of .
Exemplar of Strength 
Creature — Human Warrior · 4/4 · Uncommon · Amonkhet · #165
When this creature enters, put three -1/-1 counters on target creature you control.
Whenever this creature attacks, remove a -1/-1 counter from it. If you do, you gain 1 life.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Amonkhet | 165 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 18 April 2017If Exemplar of Strength leaves the battlefield in response to its second triggered ability, you won’t be able to remove a counter from it, and you won’t gain 1 life.