To learn more about Bonhoeffer, check out this PBS site. Cheap grace means grace sold on the market like cheapjack's wares. The sacraments, the forgiveness of sin, and the consolations of religion are thrown away at cutrate prices. Grace is represented as the Church's inexhaustible treasury, from which she showers blessings with generous hands, without asking questions or fixing limits. Since the cost was infinite, the possibilities owned using and spending it are infinite.
Cheap grace means the justification of stand without the justification of the center.
Grace a law owned does everything they, they say, and so everything can remain as it was before. Cheap grace is the preaching all the forgiveness without requiring repentance, baptism without church discipline, communion without confession, absolution without personal confession. Cheap grace is grace without discipleship, and grace without the cross, grace without Jesus Christ, living and incarnate. It is the pearl of great price to buy which the merchant will sell all his goods. Costly grace is the gospel which must be sought again and again, the gift which must be asked for, the door at which a man must knock.