Cheapest priced copy (Mirrodin Besieged): $0.35 at Card Kingdom, near mint, their price list as of .
Melira's Keepers 
Creature — Human Warrior · 4/4 · Uncommon · Mirrodin Besieged · #83
This creature can't have counters put on it.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mirrodin Besieged | 83 | Uncommon | $0.35 | $0.49 |
| The List | MBS-83 | Uncommon | $0.35 | — |
4 rulings from Wizards of the Coast
- 1 June 2011Damage from a source with infect has no effect on Melira's Keepers. No -1/-1 counters are placed on it, and no damage is marked on it. The damage is still dealt for purposes of effects that care about damage, such as lifelink.
- 1 June 2011If a creature with a counter on it becomes a copy of Melira's Keepers, those counters will remain.
- 1 June 2011If Melira's Keepers would enter with a counter on it, it simply enters without that counter.
- 1 June 2011Melira's Keepers can't have any kind of counters placed on it, not just -1/-1 counters.