Allah tells;

وَيَا قَوْمِ لا أَسْأَلُكُمْ عَلَيْهِ مَالاً إِنْ أَجْرِيَ إِلاَّ عَلَى اللّهِ ...

And O my people! I ask of you no wealth for it, my reward is from none but Allah.

Nuh says to his people, "I do not ask you for any wealth in return for my sincere advice to you.''

Wealth (Mal) here means, "payment that I take from you.''

Nuh means, "I am only seeking the reward from Allah, the Mighty and Sublime.''

Concerning the statement,

... وَمَآ أَنَاْ بِطَارِدِ الَّذِينَ آمَنُواْ ...

I am not going to drive away those who have believed.

This alludes to the fact that they (the disbelievers) requested Nuh to disassociate himself from the believers, because they were averse to them and felt themselves too important to sit with them.

This is similar to the request of disbelievers to the seal of the Messengers to disassociate himself from a group of the people who were considered weak in their social status. They wanted the Prophet to sit with them in a special gathering of the elite.

Therefore, Allah revealed,

وَلاَ تَطْرُدِ الَّذِينَ يَدْعُونَ رَبَّهُمْ بِالْغَدَاةِ وَالْعَشِىِّ

And turn not away those who invoke their Lord, morning and afternoon. (6:52)

Allah also says,

وَكَذلِكَ فَتَنَّا بَعْضَهُمْ بِبَعْضٍ لِّيَقُولواْ أَهَـؤُلاءِ مَنَّ اللَّهُ عَلَيْهِم مِّن بَيْنِنَآ أَلَيْسَ اللَّهُ بِأَعْلَمَ بِالشَّـكِرِينَ

Thus We have tried some of them with others, that they might say: "Is it these (poor believers) whom Allah has favored from among us!'' Does not Allah know best those who are grateful! (6:53)

And Nuh says here,

... إِنَّهُم مُّلاَقُو رَبِّهِمْ وَلَـكِنِّيَ أَرَاكُمْ قَوْمًا تَجْهَلُونَ ﴿٢٩﴾

وَيَا قَوْمِ مَن يَنصُرُنِي مِنَ اللّهِ إِن طَرَدتُّهُمْ أَفَلاَ تَذَكَّرُونَ ﴿٣٠﴾

Surely, they are going to meet their Lord, but I see that you are a people that are ignorant.

And O my people! Who will help me against Allah, if I drove them away! Will you not then give a thought!