paragraph: Maximilian's death came at a time when Durer was concerned he was losing "my sight and freedom of hand" (perhaps caused by arthritis) and increasingly affected by the writings of Martin Luther. In July 1520 Durer made his fourth and last major journey, to renew the Imperial pension Maximilian had given him and to secure the patronage of the new emperor, Charles V, who was to be crowned at Aachen. Durer journeyed with his wife and her maid via the Rhine to Cologne and then to Antwerp, where he was well received and produced numerous drawings in silverpoint, chalk and charcoal. In addition to going to the coronation, he made excursions to Cologne (where he admired the painting of Stefan Lochner), Nijmegen, 's-Hertogenbosch, Bruges (where he saw Michelangelo's Madonna of Bruges), Ghent (where he admired van Eyck's altarpiece), and Zeeland. Durer took a large stock of prints with him and wrote in his diary to whom he gave, exchanged or sold them, and for how much. This provides rare information of the monetary value placed on prints at this time. Unlike paintings, their sale was very rarely documented. While providing valuable documentary evidence, Durer's Netherlandish diary also reveals that the trip was not a profitable one. For example, Durer offered his last portrait of Maximilian to his daughter, Margaret of Austria, but eventually traded the picture for some white cloth after Margaret disliked the portrait and declined to accept it. During this trip he also met Bernard van Orley, Jan Provoost, Gerard Horenbout, Jean Mone, Joachim Patinir and Tommaso Vincidor, though he did not, it seems, meet Quentin Matsys. At the request of Christian II of Denmark, Durer went to Brussels to paint the King's portrait. There he saw "The things which have been sent to the king from the golden land"--the Aztec treasure that Hernan Cortes had sent home to Holy Roman Emperor Charles V following the fall of Mexico. Durer wrote that this treasure "was much more beautiful to me than miracles. These things are so precious that they have been valued at 100,000 florins". Durer also appears to have been collecting for his own cabinet of curiosities, and he sent back to Nuremberg various animal horns, a piece of coral, some large fish fins, and a wooden weapon from the East Indies. Having secured his pension, Durer finally returned home in July 1521, having caught an undetermined illness--perhaps malaria --which afflicted him for the rest of his life, and greatly reduced his rate of work. 
question: Why was it important that Durer wrote about the price of prints in his diary?
answer: Because there was a large stock of prints