Cheapest priced copy (Planar Chaos): $0.79 at Card Kingdom, near mint, their price list as of .
Dust Elemental 
Creature — Elemental · 6/6 · Rare · Planar Chaos · #5
Flash (You may cast this spell any time you could cast an instant.)
Flying; fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When this creature enters, return three creatures you control to their owner's hand.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.79 to $11.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Planar Chaos | 5 | Rare | $0.79 | $11.99 |
2 rulings from Wizards of the Coast
- 8 June 2016You may return Dust Elemental creature itself to its owner’s hand as its triggered ability resolves. If you don’t control three other creatures, you must return it.
- 8 June 2016The ability of Dust Elemental doesn’t target any creature. Because of this, no player may take action between the time you choose the creature to return and the time you return it.