Cheapest priced copy (Double Masters 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Relief Captain 
Creature — Kor Knight Ally · 3/2 · Uncommon · Archenemy: Nicol Bolas · #19
When this creature enters, support 3. (Put a +1/+1 counter on each of up to three other target creatures.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
5 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 24 | Common | $0.35 | $0.49 |
| Archenemy: Nicol Bolas | 19 | Uncommon | $0.35 | — |
| Game Night 2019 | 11 | Uncommon | $0.35 | — |
| Foundations Jumpstart | 241 | Uncommon | $0.35 | — |
| Oath of the Gatewatch | 32 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 22 January 2016Support can target a creature you don't control.
- 22 January 2016You can't put more than one +1/+1 counter on any one target using the support action.
- 22 January 2016If a spell with support has other abilities that target creatures, those abilities and the support ability can target the same creature.