Charon

Charon was the ferryman of the dead, an underworld daimon (spirit) in the service of Hades. He received the shades of the dead from Hermes, who gathered them from the upper world and guided them to the shores of River Acheron.

Unlike many other Psychopomps, Charon did not do this for free; he required a donation to be given to him. The fee for his service was a single obol, a coin  a silver coin worth a sixth of a drachma, which was placed in the mouth of a corpse at burial (It was known as Charon’s obol). People who are unable to pay the fee were doomed to wander the shores of the river for a hundred years. Since most Greeks, understandably, did not want to wander in the mists and marshes, they buried their dead with coins to pay the ferryman; this tradition is still retained in many parts of Greece.

From: https://aquileana.wordpress.com/2017/10/11/%E2%96%BAmythology-psychopomps-border-crossers-and-guiders-of-souls%F0%9F%8C%9F/