Cheapest priced copy (Universes Within): $18.99 at Card Kingdom, near mint, their price list as of .
Themberchaud 
Legendary Creature — Dragon · 5/5 · Rare · Secret Lair Drop · #728
Trample
When Themberchaud enters, he deals X damage to each other creature without flying and each player, where X is the number of Mountains you control.
You may exert Themberchaud as he attacks. When you do, he gains flying until end of turn. (An exerted creature won't untap during your next untap step.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $18.99 to $20.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Secret Lair Drop | 728 | Rare | $20.99 | $19.99 |
| Universes Within | 28 | Rare | $18.99 | — |