Cheapest priced copy (Shadowmoor): $4.99 at Card Kingdom, near mint, their price list as of .
Corrosive Mentor 
Creature — Elemental Rogue · 1/3 · Uncommon · Shadowmoor · #61
Black creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $4.99 to $22.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Shadowmoor | 61 | Uncommon | $4.99 | $22.99 |