Cheapest priced copy (Eventide): $0.35 at Card Kingdom, near mint, their price list as of .
Impelled Giant 
Creature — Giant Warrior · 3/3 · Uncommon · Eventide · #58
Trample
Tap an untapped red creature you control other than this creature: This creature gets +X/+0 until end of turn, where X is the power of the creature tapped this way.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Eventide | 58 | Uncommon | $0.35 | $0.99 |
| Salvat 2011 | 111 | Uncommon | — | — |
2 rulings from Wizards of the Coast
- 1 August 2008The power of the creature you tap is checked as the ability resolves, not as the creature is tapped, and not at any later time should the power of that creature change. If that creature is no longer on the battlefield as the ability resolves, use the power it had when it was last on the battlefield.
- 1 August 2008Since the activated ability doesn't have a tap symbol in its cost, you can tap creatures that haven't been under your control since your most recent turn began to pay the cost.