Cheapest priced copy (Lorwyn): $0.35 at Card Kingdom, near mint, their price list as of .
Changeling Hero 
Creature — Shapeshifter · 4/4 · Uncommon · Lorwyn · #9
Changeling (This card is every creature type.)
Champion a creature (When this enters, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper