Cheapest priced copy (Theros): $0.35 at Card Kingdom, near mint, their price list as of .
Lagonna-Band Elder 
Creature — Centaur Advisor · 3/2 · Common · Theros · #21
When this creature enters, if you control an enchantment, you gain 3 life.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Theros | 21 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 15 September 2013If you don't control an enchantment when Lagonna-Band Elder enters the battlefield, its ability won't trigger. If it does trigger, but you don't control an enchantment when the ability tries to resolve, you won't gain life.