What did Martin Luther criticize the sale of?

Martin Luther disgreed with the Roman Catholic Church's sale of indulgences. Indulgences were prescribed prayers or acts of virtue that could be applied to the souls in Purgatory, a place of cleansing flames to absolve them of sins they had confessed during their life time but for which they had not yet done penance. If the indulgences were performed in good faith, the departed person's time in purgatory could be shortened. The Church in Luther's era had become quite corrupt. They appointed "pardoners" who travelled around offering indulgences approved by the Pope in Rome. Unfortunately, the pardoners who became equally corrupt saw an opportunity to make money out of this scheme. The indulgences were intended to be given to people for free and were supposed to be applied to the souls in purgatory. However, the pardoners began selling the indulgences to be applied to the living person or the departed. Quite often the pardoners carried false relics to show to the people. If you have the opportunity read Geoffrey Chaucer's "Canterbury Tales". Read the Pardoner's tale because he is a prime example of the corruption. For example he carried some pig's bones which he claimed were Christ's bones and an old pillow case which he claimed was the Virgin Mary's veil.