Cheapest priced copy (Mirrodin Besieged): $0.35 at Card Kingdom, near mint, their price list as of .
Spiraling Duelist 
Creature — Human Berserker · 3/1 · Uncommon · Mirrodin Besieged · #76
Metalcraft — This creature has double strike as long as you control three or more artifacts.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Mirrodin Besieged | 76 | Uncommon | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 June 2011If Spiraling Duelist has double strike as the combat damage step begins, there will be a second combat damage step. As that second combat damage step begins, if Spiraling Duelist no longer has double strike (perhaps because an artifact creature you controlled was destroyed), Spiraling Duelist will not assign combat damage a second time.