Gold

Gold (金 kin, lit. "gold") acts as a system of money/currency in general use for the Spirit Realm introduced in the Japanese animated film Spirited Away. It is considered highly valuable by Yubaba and the other Bathhouse workers, but ultimately ends up bringing misery to those who show their greed for it.

Method of Use
Spirits seem to earn and spend gold as Humans would earn and spend money in the Human World. Gold, like money, can also be tipped to workers from generous spirits and used to exchange better Bath Tokens in The Bathhouse. A Spirit's power and influence depends on the amount of gold he or she possesses, as seen when Yubaba praises Sen for serving the generous Unnamed River Spirit who tipped The Bathhosue a large amount of gold pieces upon his leave.

Zeniba had a monogram seal apparently made of gold, which Haku, under orders from Yubaba, stole from her.

Symbolism
Many characters in the film obsess unstoppably about gold, and it is viewed as a very negative symbol in Spirited Away. No-Face, seeing the spirits' love for the currency, can create gold out of thin air with magic, but ultimately brings misfortune to those who gleefully accept it. Yubaba is also so obsessed with gold that she puts it before her family, and does not realize this until Haku tells her that "something valuable has been taken from her", upon which the gold turns into mud/dirt. While not all characters are mean-spirited like Yubaba, their reaction to gold in the film often determines their future, as seen when Aogaeru scrounges for leftover pieces of gold in the night and when two bathhouse workers ignore danger to pick up dropped pieces of gold, all of which were eventually devoured by No-Face and saved by Chihiro, who refused to accept the gold and ended up saving them from No-Face (Kaonashi)