“I didn’t want to be here...I wanted to be about 5 minutes away,” Trump said to the crowd at Drake University.
But he said he was mistreated by Fox News, which was hosting the debate.
“Fox has been extremely nice in the last number of hours,” Trump said the network invited him back.
In a statement Fox News said the billionaire "offered to appear at the debate upon the condition that FOX News contribute $5 million to his charities. We explained that was not possible and we could not engage in a quid pro quo, nor could any money change hands for any reason."
Trump said he has raised millions for veterans so far through tonight’s event -- $5 million so far from friends of his, including a million dollars of his own.
Trump also said a website the campaign created has raised over $400,000 thus far from supporters. Fellow GOP candidates Rick Santorum and Mike Huckabee attended the Trump event after the front runner extended an invitation to all his competitors.