Cheapest priced copy (Magic 2013): $0.35 at Card Kingdom, near mint, their price list as of .
Mindclaw Shaman 
Creature — Lizard Shaman · 2/2 · Uncommon · The List · #M13-142
When this creature enters, target opponent reveals their hand. You may cast an instant or sorcery spell from among those cards without paying its mana cost.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $3.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2013 | 142 | Uncommon | $0.35 | $3.99 |
| The List | M13-142 | Uncommon | — | — |
6 rulings from Wizards of the Coast
- 1 July 2012If the card has X in its mana cost, you must choose 0 as its value.
- 1 July 2012The card goes to its owner’s graveyard after it resolves (or otherwise leaves the stack), not yours.
- 1 July 2012If you cast a card “without paying its mana cost,” you can’t pay any alternative costs. You can pay additional costs such as kicker costs. If the card has mandatory additional costs, you must pay those.
- 1 July 2012You cast the card from the opponent’s hand immediately. Ignore timing restrictions based on the card’s type. Other timing restrictions, such as “Cast [this card] only during combat,” must be followed.
- 1 July 2012Any player can respond to Mindclaw Shaman’s triggered ability. However, once that ability starts resolving and the target opponent reveals their hand, players can’t respond until after the ability finishes resolving. For example, the opponent can’t cast the instant or sorcery card you choose to cast in order to stop you from casting it.
- 1 July 2012If you can’t cast any instant or sorcery card (perhaps because there are no legal targets available) or if you choose not to cast one, then Mindclaw Shaman’s ability finishes resolving and the game moves on.