The very idea of Purgatory and the doctrines that are often attached to it (prayer for the dead, indulgences, meritorious works on behalf of the dead, etc.) all fail to recognize that Jesus' death was sufficient to pay the penalty for ALL of our sins. Jesus, who was God incarnate (John 1:1,14), paid an infinite price for our sin. Jesus died for our sins (1 Corinthians 15:3). Jesus is the atoning sacrifice for our sins (1 John 2:2). To limit Jesus' sacrifice to atoning for original sin, or sins committed before salvation, is an attack on the Person and Work of Jesus Christ. If we must in any sense pay for, atone for, or suffer because of our sins - that indicates Jesus' death was not a perfect, complete, and sufficient sacrifice.http://www.gotquestions.org/purgatory.html
A place where people with Veneile sins go and they are purified by suffering and helped by prayer of family. Not mortal but veneile sins, petty sins, nickle and dime crimes and offenses. Eventually they go to heaven. Actually a pretty good policy.
A "solution" made up by the catholic church in trying to justify why people like Hitler ( who was raised in a catholic household) could possibly go to heaven. so they came up with purgatory where you go to " pay " for your sins before being allowed in heaven. Its nowhere to be found in the bible. If we need to pay for our sins, then Jesus sacrifice was a total waste of time.
Definition: “According to the teaching of the [Roman Catholic] Church, the state, place, or condition in the next world . . . where the souls of those who die in the state of grace, but not yet free from all imperfection, make expiation for unforgiven venial sins or for the temporal punishment due to venial and mortal sins that have already been forgiven and, by so doing, are purified before they enter heaven.” (New Catholic Encyclopedia, 1967, Vol. XI, p. 1034) Not a Bible teaching. ( Further answer in comments )