Indulgences
Indulgences were a relaxation of penalties for sins people committed. Some indulgences reduced the punishment a person would receive in purgatory. The church would sell indulgences in order to raise money. Rich people paid for indulgences, thus giving them and the church more power than the common people.

Purgatory
Purgatory was a place in which souls went to before going to heaven. Here, they were punished for the sins they committed. Once the sins were paid for, the souls would travel up to heaven. When the church began selling indulgences, many Christians became enraged because they believed that the church was letting people buy their way into heaven.

Indulgences and Purgatory