The Pope doesn't actually earn income, but he manages the \$300 million budget which goes to paying for all of the Pope's expenses: food, travel, the Papal apartments, among other things.
A Pope usually stays Pope until his death. The most recent retiree would be Pope Benedict XVI who [shocked the world with his resignation](http://edition.cnn.com/2013/02/11/world/europe/pope-resignation-q-and-a/) in 2013. He retired six centuries after Pope Gregory XII, who abdicated the Papal seat last 1415. A Papal retiree will have a pension package. This infographic shows how his package compares to other top professions in the UK: