Billionaire businessman Donald Trump says he is willing to spend $1 billion on his Republican presidential campaign.

Trump flew to Iowa on his private helicopter for a major campaign event that has drawn many other presidential candidates from both parties.

Asked by a reporter at the State Fair whether he would throw $1 billion of his own money into the race, Trump responded, "I would do that, yeah, if I had to."

"You saw I make $400 million a year," Trump said, "So what difference does it make?"

The real estate magnate from New York touted that he is “turning down so much money” from donors.

The GOP frontrunner vowed to do everything in his power to “make the country great again,” adding that, “We can't make it great unless we make it rich.”

In another show of wealth, a hallmark of his campaign stops, Trump offered children rides on his $7 million helicopter that is emblazoned with his name.

Trump’s campaign has been marked by controversial statements starting with disparaging remarks about Mexican immigrants as he announced his candidacy.

"I don't think I've made mistakes," he said.

The businessman took several shots at his major rivals from both camps; calling Republican Jeb Bush "a puppet to his donors," while describing the Democratic frontrunner, Hillary Clinton, the “single worst secretary of state in the history of this country."

Trump remains the frontrunner for the Republican presidential nomination following a controversial debate in which he refused to pledge loyalty to the eventual GOP nominee.

His appearance at the State Fair came as his campaign has gained traction in the early voting state of Iowa.

A recent Suffolk University survey put Trump ahead of the crowded GOP field, with 17 percent support from voters.