A Desire for Wealth and a Desire for Torah
The תורה תמימה makes a comparison between Bilaam and רב יוסי בן קסמא in Pirkei Avot.
Bilaam tells Balak that even if he gives him a house full of gold and silver, he refuses to violate the word of G-d.
Rav Yossi says to a community that offered him a lucrative financial gain to become their rabbi, the following: “If you give me all the gold and silver of the world, I refuse to live anywhere but in a place of Torah.”
Rashi concludes that Bilaam was very desirous of gold and silver. The Torah Temima says that Rav Yossi was not materialistic at all.
The difference between the two is that Rav Yossi was offered actual real wealth and he refused it. Balak only promised Bilaam honor and never promised wealth.
Bilaam revealed his true desires. Rav Yossi revealed his true love of Torah.