Cheapest priced copy (Lorwyn): $0.35 at Card Kingdom, near mint, their price list as of .
Kithkin Greatheart 
Creature — Kithkin Soldier · 2/1 · Common · Lorwyn · #25
As long as you control a Giant, this creature gets +1/+1 and has first strike.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 25 | Common | $0.35 | $0.49 |
| Modern Masters | 21 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 7 June 2013If, after dealing first-strike combat damage, Kithkin Greatheart loses first strike (perhaps because the Giant you controlled was destroyed by first-strike combat damage), it won’t deal regular combat damage.