Cheapest priced copy (Worldwake): $2.79 at Card Kingdom, near mint, their price list as of .
Jwari Shapeshifter 
Creature — Shapeshifter Ally · 0/0 · Rare · The List · #WWK-32
You may have this creature enter as a copy of any Ally creature on the battlefield.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $2.79 to $12.99 at Card Kingdom
5 rulings from Wizards of the Coast
- 1 March 2010Any "enters" abilities of the copied creature will trigger when Jwari Shapeshifter enters.
- 1 March 2010If the chosen creature is a token, your Jwari Shapeshifter copies the original characteristics of that token as stated by the effect that put the token onto the battlefield. Your Jwari Shapeshifter is not a token.
- 1 March 2010Jwari Shapeshifter copies exactly what was printed on the original creature and nothing more (unless that creature is copying something else or is a token; see below). It doesn't copy whether that creature is tapped or untapped, whether it has any counters on it or Auras attached to it, or any non-copy effects that have changed its power, toughness, types, color, or so on.
- 1 March 2010If the chosen creature is copying something else (for example, if the chosen creature is another Jwari Shapeshifter), then your Jwari Shapeshifter enters as whatever the chosen creature copied.
- 1 March 2010You can choose not to copy anything. In that case, Jwari Shapeshifter enters as a 0/0 creature, and is probably put into the graveyard immediately.