Cheapest priced copy (Throne of Eldraine): $0.35 at Card Kingdom, near mint, their price list as of .
Redcap Raiders 
Creature — Goblin Warrior · 3/2 · Common · Throne of Eldraine · #136
Whenever this creature attacks, you may tap an untapped non-Human creature you control. If you do, this creature gets +1/+1 and gains trample until end of turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Throne of Eldraine | 136 | Common | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 4 October 2019Players can't take any actions between the time you choose whether to tap a creature and the time Redcap Raiders gets +1/+1 and gains trample.
- 4 October 2019While resolving the ability of Redcap Raiders, you can't tap more than one creature to get +1/+1 more than once.
- 4 October 2019Tapping an attacking creature with vigilance to pay the cost of Redcap Raiders's ability won't cause that creature to leave combat or to stop attacking.