As I said earlier, if you get the cross, you get Christianity. If you get the cross, your soul will be convicted and by this supernatural grace, (free, unmerited favor) you cannot help but to live a life for Him who died for us. So ask yourself, Are you a Christian because you say so, or because God says so?
Dietrich Bonhoeffer addressed it this way, Cheap grace is the grace we bestow on ourselves. Cheap grace is the preaching of forgiveness without requiring repentance, baptism without church discipline, Communion without confession.... Cheap grace is grace without discipleship, grace without the cross, grace without Jesus Christ, living and incarnate.
Costly grace is the gospel which must be sought again and again and again, the gift which must be asked for, the door at which a man must knock. Such grace is costly because it calls us to follow, and it is grace because it calls us to follow Jesus Christ. It is costly because it costs a man his life, and it is grace because it gives a man the only true life. It is costly because it condemns sin, and grace because it justifies the sinner. Above all, it is costly because it cost God the life of his Son: “ye were bought at a price,” and what has cost God much cannot be cheap for us. Above all, it is grace because God did not reckon his Son too dear a price to pay for our life, but delivered him up for us. Costly grace is the Incarnation of God.
Costly grace is the sanctuary of God; it has to be protected from the world, and not thrown to the dogs. It is therefore the living word, the Word of God, which he speaks as it pleases him. Costly grace confronts us as a gracious call to follow Jesus. It comes as a word of forgiveness to the broken spirit and the contrite heart. Grace is costly because it compels a man to submit to the yoke of Christ and follow him; it is grace because Jesus says: “My yoke is easy and my burden is light.”
In the end, we are like one of the two criminals on the cross. One desired Jesus to pull Himself down along with him not acknowedging his guilt. The other knew well his guilt and accepted his penalty only to humbly ask Christ to remember him in paradise. Cheap grace puts us first telling God what to do. Costly grace puts God first as there is no other position to hold!