Cheapest priced copy (Coldsnap): $1.49 at Card Kingdom, near mint, their price list as of .
Lightning Serpent 
Creature — Elemental Serpent · 2/1 · Rare · Coldsnap · #88
Trample, haste
This creature enters with X +1/+0 counters on it.
At the beginning of the end step, sacrifice this creature.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $1.49 to $10.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Coldsnap | 88 | Rare | $1.49 | $10.99 |
One ruling from Wizards of the Coast
- 15 July 2006If Lightning Serpent enters without X being paid because an effect puts it onto the battlefield or an effect lets you cast it without paying its mana cost, then X is 0.