Cheapest priced copy (The List): $0.49 at Card Kingdom, near mint, their price list as of .
Crooked Scales 
Artifact · Rare · Mercadian Masques · #291
{4}, {T}: Flip a coin. If you win the flip, destroy target creature an opponent controls. If you lose the flip, destroy target creature you control unless you pay {3} and repeat this process.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 to $34.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mercadian Masques | 291 | Rare | $0.69 | $34.99 |
| The List | MMQ-291 | Rare | $0.49 | — |
2 rulings from Wizards of the Coast
- 4 October 2004If you pay the {3}, you do not choose a new pair of targets when it repeats. This means that if you lose the flip, you have the choice of having your creature destroyed or paying {3} to try again to win the flip. If you lose again, you get the same choice, and so on. You can keep trying to destroy your opponent’s creature as long as you have mana to pay.
- 4 October 2004You choose both targets on activation, so you can only activate this when you can legally choose both targets.