Cheapest priced copy (Lorwyn): $0.69 at Card Kingdom, near mint, their price list as of .
Ashling's Prerogative 
Enchantment · Rare · Lorwyn · #150
As this enchantment enters, choose odd or even. (Zero is even.)
Each creature with mana value of the chosen quality has haste.
Each creature without mana value of the chosen quality enters tapped.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.69 to $10.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 150 | Rare | $0.69 | $10.99 |
2 rulings from Wizards of the Coast
- 1 October 2007The "chosen value" is either "odd" or "even." So either creatures with odd mana values enter tapped and creatures with even mana values have haste, or vice versa.
- 1 October 2007If a creature has X in its mana cost, that X is treated as 0 for the purposes of these effects. It doesn't matter what the value of X was while the creature was on the stack.