Cheapest priced copy (Fallen Empires): $0.35 at Card Kingdom, near mint, their price list as of .
Merseine 
Enchantment — Aura · Common · Fallen Empires · #23c
Enchant creature
This Aura enters with three net counters on it.
Enchanted creature doesn't untap during its controller's untap step if this Aura has a net counter on it.
Pay enchanted creature's mana cost: Remove a net counter from this Aura. Only the controller of the enchanted creature may activate this ability.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
4 printings · $0.35 to $0.39 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fallen Empires | 23a | Common | $0.35 | — |
| Fallen Empires | 23b | Common | $0.39 | — |
| Fallen Empires | 23c | Common | $0.35 | — |
| Fallen Empires | 23d | Common | $0.35 | — |
2 rulings from Wizards of the Coast
- 4 October 2004Can remove as many counters per turn as you want to and this can be done at any time instants are legal.
- 4 October 2004The cost that needs to be paid includes colored mana requirements.