What is a sacrament in christianity? and explain each one simply.. eg marriage

A sacrament is a Christian rite recognised as of particular importance and significance. There are various views on the existence and meaning of such rites. Many Christians consider the sacraments to be a visible symbol of the reality of God, as well as a means by which God enacts his grace. Many denominations, including the Anglican, Catholic, Lutheran, Methodist and Reformed, hold to the definition of sacrament formulated by Augustine of Hippo: an outward sign of an inward grace that has been instituted by Jesus Christ.[1][2][3][4][5] Sacraments signify God's grace in a way that is outwardly observable to the participant.[5]

A sacrament is a Christian rite recognized as of particular importance and significance. 

And there are 7 sacraments. But here is one of them:

The sacrament of Confession is a regular sacrament we recieve our whole lives where we are always given a chance to repent our sins in everyday life. This is voluntary, as compared to the sacrament of Annointment where a dying person cannot repent anymore for his sins so the priest is the one that does it for him. 

Complementary goods. they go together, thats why one price increase and the others demand increases