Cheapest priced copy (Kaladesh): $0.35 at Card Kingdom, near mint, their price list as of .
Fairgrounds Trumpeter 
Creature — Elephant · 2/2 · Uncommon · Kaladesh · #155
At the beginning of each end step, if a +1/+1 counter was put on a permanent under your control this turn, put a +1/+1 counter on this creature.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kaladesh | 155 | Uncommon | $0.35 | $0.49 |
| March of the Machine | 335 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 20 September 2016If a +1/+1 counter hasn't been placed yet at the moment an end step begins, Fairgrounds Trumpeter's ability doesn't trigger at all. If another ability triggers during the end step and puts a +1/+1 counter on a permanent you control, you won't put an additional +1/+1 counter on Fairgrounds Trumpeter.
- 20 September 2016Fairgrounds Trumpeter's ability triggers if, at any point during this turn, a +1/+1 counter was placed on a permanent that you controlled as the counter was placed. It doesn't matter whether you still control the permanent or whether it still has a counter.