Cheapest priced copy (Dark Ascension): $0.49 at Card Kingdom, near mint, their price list as of .
Counterlash 
Instant · Rare · Dark Ascension · #33
Counter target spell. You may cast a spell that shares a card type with it from your hand without paying its mana cost.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.49 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dark Ascension | 33 | Rare | $0.49 | $1.49 |
| The List | DKA-33 | Rare | $0.59 | — |
3 rulings from Wizards of the Coast
- 22 January 2011If the card has {X} in its mana cost, you must choose 0 as its value.
- 22 January 2011If 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.
- 22 January 2011You cast the card in your hand as part of the resolution of Counterlash. Timing restrictions based on the card’s type (such as creature or sorcery) are ignored. Other restrictions are not (such as “Cast [this card] only during combat”).