Anyone have any recommendations for online resources regarding the history of the buying and selling of church offices, or of how church offices were inherited at certain points in history?
Simony (ie., ecclesiastical corruption for financial gain) was such a widespread problem for the Roman Catholic Church for centuries before the Council of Trent that any treatment of the Reformation that covers the abuses of Tetzel and the like will give examples of simony. John Calvin (The Necessity of Reforming the Church and the Institutes -- see his famous quotes from the Institutes: "I maintain that, in the Papacy in the present day, scarcely one benefice in a hundred is conferred without simony, as the ancients have defined it (Calv. in Art. 8:21)."), Dante Alighieri (Divine Comedy, and Blaise Pascal (Provincial Letters) are some notables who have written against simony in their day. (Calvin himself received a benefice at age 12.) Pope Gregory VI deposed himself for the sin of simony, and canon law was later instituted (law of Julius II, 1503) to prevent the election of simonist popes.
Wycliffe writes on the topic, see "Adovcates of Reform" in Library of Christian Classics. For online: Do a search on google w "Wycliffe" & "Simony" to locate online material.