Cheapest priced copy (The List): $0.99 at Card Kingdom, near mint, their price list as of .
Dominus of Fealty 
Creature — Spirit Avatar · 4/4 · Rare · Eventide · #102
Flying
At the beginning of your upkeep, you may gain control of target permanent until end of turn. If you do, untap it and it gains haste until end of turn.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.99 to $29.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2011 | 194 | Rare | $1.29 | — |
| Eventide | 102 | Rare | $1.49 | $29.99 |
| The List | CMD-194 | Rare | $0.99 | — |
One ruling from Wizards of the Coast
- 1 August 2008If you already control the targeted permanent when the ability resolves, you still need to choose whether or not to apply the effect. If you choose to apply it, the permanent untaps and gains haste. If you don’t, it doesn’t.