On Saturday night, at the White House Correspondents dinner, President Obama jabbed Donald Trump for inflating the size of his fortune.

In fact, the president has no idea how rich Trump is. And neither does anyone else.  

Trump himself says he is worth upwards of $10 billion. Last July, Bloomberg News put the number at $2.9 billion. This week, Forbes Magazine’s conservative estimate is $4.5 billion.  

Why quibble over a few billion dollars? Let’s just stipulate that Donald Trump’s fortune is like Hillary Clinton’s wardrobe of pantsuits—not infinite but sufficiently large to get through a presidential campaign.

Not everyone gets this.  Recently, on "Face the Nation," the panel chewed over poor Trump’s financial challenges.

“How’s he going to raise money?” asked  Reihan Salam, the executive editor of National Review. “He’s been promising that he's a self-funder this entire time, and the Democrats are going to have tremendous resources at their disposal.”

“That’s right,” said CBS anchor John Dickerson. “He’s going to have to find somebody to fund this general election…it’s super expensive.  But one of his arguments is, ‘I’m self-funded, I'm not bought and paid for. How's he going to fix that?”

I think Dickerson and Salam may be unduly concerned.

In the 2012 campaign, Romney and Obama each spent roughly a billion dollars. Theoretically, Trump could put up that much himself, using available liquid assets (estimated by Forbes at more than $350 million and by Trump himself at much more) and by selling real estate properties.   If he loans the money to his campaign, as he has done in the primaries, he has the prospect of recouping it after the election.  Or, if he really is a Ten Billion Dollar Man, he could just tithe the entire campaign to himself.

He can save, too. Trump owns his campaign headquarters, his plane and many businesses that provide goods and services.   A lot of what his campaign shells out on the trail (like hotels, food and beverage and wardrobe) could wind up back in his own pocket.

Forbes awards Trump zero value for his brand. That might be good accounting but it ignores the real-word importance of publicity.  If Trump wins (and even if he loses) there won’t be a person on the planet who doesn’t know the Trump name.  That kind of recognition is of incalculable value to what is, after all, a family business that the candidate hopes to pass along to future generations of the House of Trump.  

So Trump is loaded. And as this year’s primaries have shown, money isn’t everything. There are alternatives to kissing up to big donors and winning good government Brownie points at the same time. 

Bernie Sanders has demonstrated the efficacy of just asking a motivated audience for help, a tactic that has netted him almost $200 million dollars in checks averaging  “twenty-seven bucks” (unfortunately I can’t write this in a Brooklyn accent). 

Trump supporters are far more numerous, at least as enthusiastic -- and almost certainly flusher-- than Bernie’s army of college kids. Whatever Trump takes in this way he will frame as an example, a la Bernie, of reaching out to "The Little People" over the heads of the rich.

Trump also knows that the best things in life can be free. Four years ago, the Obama and Romney campaigns each spent roughly half their money on TV ads. Trump gets most of his screen time for free. In mid-March, the New York Times reported that he had garnered almost two billion dollars’ worth of free exposure — vastly more than any other candidate.

Hillary’s share of free media will grow in the general election, but it won’t be as valuable as Trump’s.  He is a masterful and ratings-booting performer.  Hillary is a professional politician without a lot of charisma. She is much better in scripted and produced ads.  Those cost a lot of money.

There’s no doubt that Hillary can raise TV money. But when she does, Trump will make her pay for it by amplifying Bernie Sanders’ message that Secretary Clinton is the bought-and-paid-for puppet of Wall Street and big business. He is going to make Saint Bernie a star this autumn and “Crooked Hillary” into a villain. This puts Hillary in an infuriating trick bag. The more money she raises from her rich donors, the guiltier she looks.

So, no, I don’t know how much money Trump has.  I don’t know how much he will need, either. But I believe he is ready, willing and able to spend whatever it takes to win in November. 

The Donald is an ego-driven narcissist who has staked his reputation, his legacy and his sense of self-worth on finishing first. 

At this stage of his career, he can afford anything except losing.

Zev Chafets is a Fox News contributor. His latest book is "Remembering Who We Are: A Treasury of Conservative Commencement Addresses" (Sentinel 2015).