Cheapest priced copy (Planar Chaos): $0.35 at Card Kingdom, near mint, their price list as of .
Bog Serpent 
Creature — Serpent · 5/5 · Common · Planar Chaos · #84
This creature can't attack unless defending player controls a Swamp.
When you control no Swamps, sacrifice this creature.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Planar Chaos | 84 | Common | $0.35 | $0.49 |