Cheapest priced copy (Avacyn Restored): $0.35 at Card Kingdom, near mint, their price list as of .
Rush of Blood 
Instant · Uncommon · Avacyn Restored · #154
Target creature gets +X/+0 until end of turn, where X is its power.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Avacyn Restored | 154 | Uncommon | $0.35 | $0.99 |
One ruling from Wizards of the Coast
- 1 May 2012The value of X is determined when Rush of Blood resolves. The bonus won’t change later in the turn if the creature’s power changes.