former military Head of State, Major-General Muhammadu Buhari (rtd.), has said he would fund his presidential campaign principally from funds generated by friends, associates and well-wishers.

It also expected that the All Progressives Congress (APC)-controlled states would contribute to his campaign should he secure the ticket of the party

A close ally of Buhari who spoke anonymously to THISDAY in Abuja yesterday, said Buhari is not the typical rich Nigerian politician with loads of cash to spend.
Source: http://www.ereporter.com.ng/index.php/political-news/item/644-2015-election-buhari-reveals-how-he-plans-to-fund-his-presidential-campaign

No matter the source of the fund, provided the election doesn't end with do or die affair, Nigerians will be ok with it.