Heaven Coins are the currency of Heaven, which can be obtained from the destroyed bodies of Ghosts. These were perhaps stolen or eaten by them, and can be retrieved by the angels after being defeated. Panty and Stocking must collect a specific quantity of Heaven Coins in order to return to Heaven.
These coins are gold-colored and have a capital 'H', with wings emblazoned on them.
Usually, the strength of the ghost determines the amount of coins the Anarchy sisters can retrieve. For example, Loser Ghost, an extremely weak ghost, dropped only half a coin upon being defeated, while Queen Bee, a much stronger ghost, dropped 8 coins.
Manufactured ghosts created from ghost machines do not leave any Heaven Coins behind. Foreign Heaven Coins also exist: they are blue in color, but almost worthless compared to normal Heaven Coins.
It is possible the reason why the Anarchy sisters get so much little currency, is because of their bad attitude.