Cheapest priced copy (Planar Chaos): $0.35 at Card Kingdom, near mint, their price list as of .
Dust Corona 
Enchantment — Aura · Common · Planar Chaos · #97
Enchant creature
Enchanted creature gets +2/+0 and can't be blocked by creatures with flying.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Planar Chaos | 97 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 1 May 2007Creatures with the Reach ability (such as Giant Spider) can block this because they don’t actually have Flying.