Can Donald Trump Buy His Way Into the White House?

It costs a pretty penny to win a presidential campaign and Donald Trump is "really rich," but is it enough?

It costs a pretty penny to win a presidential campaign and Donald Trump is "really rich," but is it enough? Forbes reporter Dan Alexander tells ET that the billionaire might not have as much coin as he says.

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"I don't need anyone's money," Trump said during a press conference on Tuesday announcing his candidacy. "I'm not using the lobbyists. I'm not using donors. I don't care."

While there's no doubt that he's wealthy, the amount of money Trump is touting is being challenged.

"He claims he's worth $8.7 billion. We think it's more like $4.1 [billion]," Alexander told ET. "The biggest discrepancy is that he says that his brand is worth $3.3 billion, which is almost as much money as he's made from all of the rest of his business in his life. We put it more at about $250 million, and that even might be generous."

One thing Trump claims he's not spending money on is actors. A recent Hollywood Reporter headline alleged that Trump's campaign paid for celebrity supporters, but his camp denies the fact to ET, "Donald Trump nor his presidential campaign have ever paid to have someone at a Trump event."

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Trump officially threw his hat in the presidential ring on Tuesday.

"Quite simply, it is time to bring real leadership to Washington," the 69-year-old Celebrity Apprentice boss said. "The fact is, the American dream is dead -- but if I win, I will bring it back bigger and better and stronger than ever before."