ROCHESTER, N.H. — Expressing confidence that American voters do not care if he lacks specifics, Donald J. Trump says he has yet to fully exploit his personal advantages over his Republican presidential rivals — chiefly his enormous wealth and celebrity — and that both will matter more to his political fate than debate performances like his shaky one this week.

Mr. Trump said in an interview that he was prepared to spend $100 million or more to become the Republican nominee and that most of it would go to galvanizing voter support in states with early nominating contests. While he boasted last month that he would spend $1 billion if need be, he said that a realistic amount would be far less and that he would count on the national Republican Party for financial help if he became the nominee.

He also predicted that the extensive media coverage of his campaign would help him win caucuses and primaries in every region of the country, saying that he had planned to spend $15 million on campaign commercials this summer but did not because of the “free nationwide publicity” that the cable news networks provided.

After three months surging in Republican polls and putting rivals like Jeb Bush, a former governor of Florida, and Gov. Scott Walker of Wisconsin on the defensive, Mr. Trump faced increasingly combative opponents in Wednesday’s debate — particularly the business executive Carly Fiorina, who confronted him repeatedly. He drew some harsh notices for his vague and blustery answers — as well as for his decision, at a rally here on Thursday night, to breeze past an audience member’s false statement that President Obama was a Muslim.