What do we learn from "Emes Kenei v'Al Timkor"?
Brachos 5a-b: If one engages in Torah and Chesed and buries his children, all of his sins are pardoned. It says "b'Chesed v'Emes Yechupar Avon." Our verse teaches that "Emes" refers to Torah.
Avodah Zarah 4b: An individual should not pray Musaf during the first three hours of the day on Rosh Hashanah. Hashem engages in Torah then, which is called Emes; He does not go beyond the letter of the law at this time. After this, He judges; Din is not called Emes. Then He goes beyond the letter of the law.
Rashi citing Bechoros 29a: If one cannot find a Rebbi to teach him for free, he should pay to learn - "Emes Keneh." Do not say, just like I paid to learn Torah, I will charge to teach - "v'Al Timkor."
R. Yonah: Distribute your money to acquire Chachmah, and do not sell it for any profit after you learned it. I.e. do not abandon engaging in Torah to engage in business, and you will forget it. Even if your business profits thousands of gold and silver coins, one should not sell Torah or exchange it for gold and many pearls.
Malbim: Even though you pay a high price for Emes - your desire, amusement of youth and yearning of your Nefesh, give the price, and do not sell. I.e. do not buy it like a merchant who buys in order to sell at another [higher] price. I.e. you learn in order to attain wealth or honor - this is like buying and selling. He buys in order to sell at another price. Emes is when one does it for its own sake.
Why does the verse conclude "Chachmah u'Musar u'Vinah"?
Malbim: This is the Emes that one should buy. Chachmah includes the laws of Midos and conduct that the Torah mandates. All its matters are received. Man's Binah does not find them, and they are opposite to his nature. Desire argues with the laws of Chachmah. The Nefesh can accept the laws of Chachmah only via Musar; Musar's root is in Yir'as Hashem. He fears Hashem, who looks at him, and His punishment; He commanded about the laws of Chachmah. The person afflicts his Nefesh with the ropes of fear, not to transgress its mouth, then he will acquire also Binah. Binah [decides] between Emes and Sheker in matters that depend on investigative intellect. However, if he accepts the laws of Chachmah with Musar until it is truly fixed in his heart, that he believes in Hashem who carved its laws, and He knows their reasons, then he can understanding a matter amidst another matter, and derive consequences. This is via acquiring Emes. He believes in the laws of Chachmah, that they are Emes.