By the start of this month, Donald Trump’s presidential campaign had spent only about $5 million since its launch—on travel, consultants, and producing his trademark “Make America Great Again” gear. The billionaire Republican frontrunner has managed to avoid spending on television ads, traditionally the costliest campaign expense, thanks to the saturation coverage his bid garnered gratis from the major news networks.
“I thought I’d have $25 million spent by now on ads,” Trump told Fortune in an interview last week. “Do you know how much I’ve spent? Zero. Because I haven’t had to.”
That may be about to change. The novelty of Trump’s bid and the bombast that fueled it have worn thin enough that cable networks no longer feel compelled to carry his events live. Trump himself has clearly noticed, grumbling Sunday on Twitter that he had to supply an aerial shot of a Jacksonville, Florida rally to demonstrate its size “because the media won’t.”
And the downshift in coverage—combined with his dip in Iowa, where polls show he’s now tied with retired neurosurgeon Ben Carson—could convince Trump to finally open that “yuge” wallet to start spending on airtime.
For his part, Trump says he’s ready and able. “I have a $605 million cash flow this year, do you think this matters to me?” he said in the interview.
The historical record, however, presents a mixed verdict on super-wealthy candidates who decide to self-fund. Take the four most expensive self-funding bids of the last quarter-century. In 2015 dollars, all topped out around a low nine-figure sum. Yet only two of the candidates—Mike Bloomberg, for New York City mayor, and Rick Scott, for Florida governor—won office. Both are high-profile jobs, to be sure. But the competition is considerably stiffer for the biggest prize, as Ross Perot learned spending $108 million in today’s dollars on his independent 1992 presidential campaign. Perot secured 19 percent of the vote, the greatest slice of the electorate for a non-major party candidate in a century. Yet he failed to carry a single state.
And the Perot bid may be the most instructive for Trump. The two share more in common than an outsize net worth and a hunger for the White House: There’s ample evidence Trump’s base traces its lineage to the constituency supporting Perot. The major difference between their candidacies, for now, is that Trump is seeking the nomination of a major party. If he secures it, he could presumably holster his checkbook while the GOP apparatus grinds into gear for the general election. Of course, that remains a long way away.
A version of this article appears in the November 1, 2015 issue of Fortune with the headline “What self-funders spend.”