Cheapest priced copy (Commander 2015 Oversized): $1.49 at Card Kingdom, foil, near mint, their price list as of .
Meren of Clan Nel Toth 
Legendary Creature — Human Shaman · 3/4 · Mythic · Tarkir: Dragonstorm Commander · #297
Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
9 printings · $1.49 to $39.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 49 | Mythic | $3.49 | — |
| Commander Anthology | 186 | Mythic | — | $6.99 |
| Commander Masters | 346 | Rare | $2.99 | $6.99 |
| Commander Masters | 584 | Rare | — | — |
| Commander Masters | 685 | Rare | $4.49 | $6.99 |
| Commander 2015 Oversized | 49 | Mythic | — | $1.49 |
| The List | C15-49 | Mythic | $2.99 | — |
| Secret Lair Drop | 52 | Mythic | — | $39.99 |
| Tarkir: Dragonstorm Commander | 297 | Mythic | $3.49 | — |
6 rulings from Wizards of the Coast
- 4 November 2015If a creature card in your graveyard has {X} in its mana cost, X is 0.
- 4 November 2015Experience counters are the second kind of counters a player can have, joining poison.
- 4 November 2015Each game pack includes a card labeled “Experience” with the suggestion “Place your experience counters here.” This card isn’t required for play. It’s simply a convenient spot to put your experience counters, which can be represented with dice, glass beads, or other small items.
- 4 November 2015If Meren of Clan Nel Toth leaves the battlefield at the same time as other creatures you control die, its first ability will trigger for each of those creatures.
- 4 November 2015You can’t choose to put the creature card into your hand if its mana value is less than or equal to the number of experience counters you have as the ability resolves.
- 4 November 2015All experience counters are identical, no matter how you got them. For example, the last ability will count experience counters that you got from the first ability, from another ability, from proliferating, and so on.