What did Hashem mean when He said to Bil'am "Im Likro l'cha Ba'u ha'Anashim ... "?
Rashi: Hashem allowed him to go, provided he went purely for financial gain.
Ramban #1 (citing the Ibn Ezra): Hashem allowed him to go because he insisted. 1
Ramban #2: He did nothing wrong in asking Hashem a second time whether he should go or not. 2 And Hashem now permitted him to go, provided they called him to come in an advisory capacity and not to curse Yisrael
See the Ramban's objection to this explanation, even though it seems to conform to the Gemara in Makos, 10b, which explains that Hashem now allowed Bil'am to go because 'be'Derech she'Adam Rotzeh Leilech, Molichin oso'. Refer also to 22:35:1:1.
Ramban: Without fear of Balak.
Having stated unequivocally that Bil'am would only be permitted to say what Hashem told him to say, why did he opt to go with the men?
Rashi: Because he thought that he would be able to talk Hashem into allowing him to curse Yisrael.