Cheapest priced copy (Lorwyn): $0.35 at Card Kingdom, near mint, their price list as of .
Fistful of Force 
Instant · Common · Lorwyn · #212
Target creature gets +2/+2 until end of turn. Clash with an opponent. If you win, that creature gets an additional +2/+2 and gains trample until end of turn. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 212 | Common | $0.35 | $0.49 |