Cheapest priced copy (Shadowmoor): $0.35 at Card Kingdom, near mint, their price list as of .
Barrenton Medic 
Creature — Kithkin Cleric · 0/4 · Common · Shadowmoor · #4
{T}: Prevent the next 1 damage that would be dealt to any target this turn.
Put a -1/-1 counter on this creature: Untap this creature.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $4.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Shadowmoor | 4 | Common | $0.35 | $4.99 |
One ruling from Wizards of the Coast
- 1 May 2008You put the -1/-1 counter on Barrenton Medic as a cost. That means it happens when you activate the ability, not when it resolves. If paying the cost causes the creature to have 0 toughness, it’s put into the graveyard before you can untap it and before you can even pay the cost again.