In days of old, the Ferrymen would carry a departed soul to the afterlife for the small sum of two coins pressed into the corpse's eyes upon death. This is no longer the case. The cost of dying has gone up.
Now the Ferrymen do not honor the oboli of Stygia, the coins that have the Mask of Charon imprinted on one side and the High Court of Stygia on the other. There are denizens of the Shadowlands who do, however. The Hierarchy uses Stygian coins as the currency for its soul-economy. Souls, relics, artifacts - all have a price.
The base Stygian coin is called an obolus. Oboli are often broken into half-oboli, quarter-oboli, and even a "drachma", which is just a sliver of an obolus. The obolus is made of Stygian iron, and each obolus piece will mystically merge with other obolus slices. Therefore, two half-oboli will huddle together and eventually merge to form an obolus. Likewise, a collection of drachma will eventually melt together and re-form into a contiguous coin.
There is currently no known way to debase the obolus, although the Renegades have been looking for an Artificer who can do so.
A wraith's Wealth Background indicates three things: how amny oboli she has at the beginning of the chronicle, what kind of wraithly resources she has available, and how much credit wraith merchants are willing to extend to her. Abviously, characters who are very new should not be allowed to take this Background, as its possession implies that a wraith has spent some time formulating a method by which to receive regular wealth.
You have no source of income, but own a cache of valuables that might be cashed in at some later date. You start with two oboli.
You are a reasonably well-off wraith, and you get a few oboli now and then through performing various services. You start with three oboli.
You have a small savings of oboli and a regular clientele. You strat with five oboli and receive half an obolus per story.
You have a cache of valuables and have found a surefire way to make oboli. Other wraiths work for you and give you a portion of their proceeds. You start with six oboli and receive one obolus per story.
You have a regular source of income and several caches of valuables. You start with seven oboli and receive three oboli per story.