Cheapest priced copy (Commander Anthology): $0.35 at Card Kingdom, near mint, their price list as of .
Azorius Keyrune 
Artifact · Uncommon · Commander Anthology · #209
{T}: Add {W} or {U}.
{W}{U}: This artifact becomes a 2/2 white and blue Bird artifact creature with flying until end of turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2013 | 236 | Uncommon | $0.39 | — |
| Commander Anthology | 209 | Uncommon | $0.35 | — |
| RNA Guild Kit | 23 | Uncommon | $0.35 | — |
| Return to Ravnica | 225 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 15 April 2013Activating the ability that turns the Keyrune into a creature while it's already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.
- 15 April 2013Until the ability that turns the Keyrune into a creature resolves, the Keyrune is colorless.