When it comes to candidates who reject donations from PACs, there are, at least in the current election cycle, two kinds: those who self-fund and those who depend on a network of small donors.
Self-funded presidential campaigns may seem like a good idea from the perspective of people such as real estate mogul Donald Trump and his supporters, but recent historical precedent shows that political campaigns funded by the candidates themselves don't have great chances of success. Trump has touted the fact that his self-funded presidential campaign means that he is not tied to any third-party interests, but rather, only the interests of the American people, and possibly his own. But in reality, this hasn't always been a successful strategy.
Self-funded campaigns have been traditionally unsuccessful
Eric Uslaner, a professor of government and politics at the University of Maryland, wrote in the New York Times about the failures of self-funded candidates. He noted that these individuals often make bad investments when they run, and in pointing to an OpenSecrets.org chart, that they tend not to win.
"Self-funding hasn't always been a successful strategy."
The website tracking the influence of money in U.S. politics charted the top self-funders currently serving in Congress. Of the top 10 self-funders in recent runs for seats in the House, funding totals ranged from roughly $1.4 million to $5 million. Six of those individuals lost their campaigns. Only Thomas MacArthur, R-N.J., ($5 million), Curt Clawson, R-Fla., the one incumbent on the chart to win, (little more than $4 million), Dave Trott, R-Mich., (about $3.6 million) and Richard Allen, R-Ga., (roughly $1.1 million), won seats in the House.
Self-funded candidates running for Senate had even less luck. Their self-contributions had a wider range, from $574,500 to more than $5.6 million. Eight of them lost their elections. Only incumbent and Senate Majority Leader Mitch McConnell, R-Ky., ($1.8 million) and David Perdue, R-Ga., ($3.9 million), won seats in the Senate.
Meg Whitman, who announced a run for governor of California in 2009, ended up self-funding her campaign in record-breaking fashion. Through the 2010 gubernatorial campaign Whitman ended up investing around $144 million of her own personal fortune into the race, according to the Huffington Post. However, the chairwoman, president and chief executive officer of Hewlett-Packard lost to Jerry Brown, whose campaign spent a small fraction – around $36.5 million – of what she did in her doomed run for California governor. The amount Whitman dropped on her campaign ended up breaking Michael Bloomberg's previous self-funding record of $109 million.
At several levels of government self-funded campaigns have been shown to have a losing track record. However, Trump is still banking on the fact that the electorate will identify his own self-funded campaign with independence from third-party interests and the freedom to say whatever he wants, which he does. If historical precedent means anything in the current presidential election cycle, though, Trump's self-funding will only go so far.

Sanders hopes small donors will lift him to the White House
Meanwhile, another candidate has avoided using PACs or his own bank account to fund his campaign. Sen. Bernie Sanders, I-Vt., is hoping to be nominated on the Democratic ticket running solely on small donations from a vast grassroots network he and his staff have constructed. The New York Times, in reporting on Sanders' use of small donors, told the story of Donna Mae Litowitz, a Miami Beach retiree. She sent $10,000 to the Vermont senator's campaign, and though Sanders and his staff sent $7,300 back to her due to campaign finance rules, her eventual $2,700 still qualified her as one of his "big donor[s]," according to the newspaper.
The Democratic candidate has raised about $73.5 million, almost 98 percent of all his donations, via small monetary gifts, according to The New York Times. In all, Sanders has raised around $75 million by his most recent filing with the Federal Election Commission in January.
"Sanders has raised around $75 million."
"We will be greatly outspent, yes, but we will raise enough money to wage a winning campaign," he said in an interview, according to the news outlet.
Sanders, as well as Trump – though Trump's war chest is likely much larger than that of Sanders via his vast personal fortune – are each testing the notion that in a post-Citizens United world, a candidate cannot win an election without tapping into a network of billionaires and PACs for contributions. Most pundits believe that neither candidate – each of whom are considered "outsiders" due to their funding policies and political beliefs – will be tapped as their respective parties' nominees. However, the prevailing notion that neither Trump nor Sanders will ultimately win the election is doing little to deter them from testing the state of campaign financing in contemporary politics.