This is going to be an unthinkably expensive election. Case in point: estimates of spending on the presidential race stretch as high as $10 billion.

This new big money free-for-all comes from the loosening of campaign finance laws through court decisions like Citizens United v. FEC. It means campaigns are finding ever-newer ways to operate — and no two of those models are exactly alike. The Washington-based Campaign Finance Institute broke down the data from campaigns and superPACs this week, and that data indicates that 2016 presidential candidates have cobbled together a variety of strategies for staying running.

For example, some candidates like Ted Cruz find themselves relying heavily upon millionaires. Here's a look at his distribution of donors:

Of the nearly $51 million his campaign and superPACs have taken in, the overwhelming majority (71 percent) comes from donations of $1 million or more. Meanwhile, only 11 percent has come from small donors, giving $200 or less.

That's just one example, but lots of different candidates' donor patterns tell fascinating stories.

To see all of these candidates' charts in one place, click here. Otherwise, read on about five different models of how candidates are fundraising in the new, big-money landscape:

The small-donor powerhouses

Let's start with the people like Bernie Sanders— those who are most dependent on grassroots support. He's known for his masses of small donors, and he's joined by Ben Carson on the Republican side.

Huge bases of small donors make for some big advantages — it means lots of people who are (literally) invested in your success, not to mention all the data that comes with those donations. And then there's another big boost: it means a lot of people who have given less than $2,700, the legal limit for contributions...meaning a candidate can go ask those people for more later.

But relying on these donors brings with it two tough questions: One, can you compete with your millionaire-backed competition? And two, how much can you grow?

"The question really is what's going to happen going forward: could Bernie Sanders — he has these people who have all donated — can he go out and bring in more people?" said Glavin. Ron Paul's 2012 run is another example of a campaign that, like Sanders' and Carson's, had a big small-donor base — but one that never managed to grow, Glavin points out.

"We've seen candidates in the past who bring in all these small donations who have trouble branching out beyond their base group," he said.

The campaign-heavy candidates

A few candidates have charts that look almost-grassrootsy. These are people who still have a lot of smallish donors, but most of them are in that second category of $201 to $2,700 donors.

It's true that Hillary Clinton and Rick Santorum are very different candidates, in the sense that she has huge amounts of money ($62.7 million) and he has very little (around $600,000). But what they have in common is that they are relying on these bigger small donors who heavily fund their campaigns, as opposed to their superPACs.

One other defining characteristic of these candidates is that they all have relatively high shares of "maxed-out" donors — that is, people who have given their campaigns the maximum legal limit of $2,700. That's more than 60 percent for Clinton and O'Malley, according to the New York Times, and nearly 50 percent of Santorum's donors.

This is good for them in one sense: having a lot of people willing to max out to you both means big money and big support.

But it comes with a risk: where do you really go from there?

"If you have thousands of people who have given you $25 or $50 and you have their email address you can go back to those people and ask to give to you again, which is easier than going out and finding a new person to give you $2,700," said Glavin.

So that could mean either having to reach out to those new donors via outside groups or having to find new campaign donors.

The big money candidates

Speaking of massive outside-spending firepower, these candidates get a huge share of their money from million-dollar-plus donations. Most of them have heavily skewed charts, but Jeb Bush — the biggest-money candidate — is the exception. However, his total $114-million haul, including 24 donors at the million-plus level and 21 more in the $500K+ group, means he's also leaning heavily on uber-wealthy donors.

Huckabee is a bit of an outsider here — he has far less money than the others ($5.6 million, compared to $20 million for Walker, the next lowest). But those million-plus donations also make up more than half of his fundraising total. These are, for now, his bread and butter.

These candidates are perhaps benefiting most from the post-Citizens United landscape. SuperPACs can take in donations of unlimited size, and these candidates have taken advantage of that to the greatest degree — in some cases while receiving relatively little grassroots support.

One big caveat here — Walker's figures only reflect superPAC data, not his campaign itself because he announced his candidacy after the most recent filing deadline. When his next quarterly campaign finance report comes out, it may change this drastically. However, he pulled in a respectable enough haul from millionaires — $12.7 million — through his superPAC that we're putting him here.

The sticking-it-out candidates

Though this group has a range of candidates, they have three things in common: they are far behind the top GOP candidates in fundraising, they're far behind in the polls, and they don't stand out for being heavily skewed towards either lots of grassroots support or lots of millionaire support.

But almost all of them are getting a good amount of their funding from donations of $500,000 or more. That means superPACs are allowing these candidates to hang around longer — perhaps much longer — than they might have in past races. (Pataki is clearly something of an exception here, but those bigger-than-$2,700 donations to his superPAC are still helping him hold on.)

"Some of these candidates can really, are really going to be able to hang on longer than they would have in the past," says Glavin. He points to former Minnesota Gov. Tim Pawlenty's campaign four years ago. Still struggling to get a foothold in August 2011, Pawlenty dropped out. But here we are, nearly to the end of August 2015, and all the major candidates are still going strong. Even Perry — who famously quit paying his South Carolina staff — is still holding on, in part thanks to big superPAC donations.

And a handful of these candidates may have even more unknown funds helping them hang on longer: Christie, Jindal, Perry, and Pataki all have 501(c)(4) groups supporting them, according to the Center for Responsive Politics. Those groups don't have to reveal any donor information. (In addition, Bush, Huckabee, and Rubio also have 501(c)(4)s. But they also have so much millionaire support that we put them in that category.)

So it's possible that these groups, were their information revealed, could drastically change these candidates' donation distributions. We do know, for example, that Jindal has $5 million more in outside donations. But we just can't know what all of his fundraising looks like. Either way, that extra money could help him hang on much longer than he otherwise would.

(Once again, a caveat: Christie has not yet had to file paperwork for his campaign, so we don't know what those donations look like.)

The Self-Reliant Candidates

Consider this one of the few things Donald Trump and Lincoln Chafee have in common: they both are leaning heavily on their own funding.

You'd think from looking at their charts that these two belonged in the campaign-dependent group. But this data only reflects donations, so it doesn't include the money candidates give or loan themselves...and those donations from other people are, for both these guys, pretty small.

And Chafee and Trump are almost entirely self-funded. As of June 30, $1.8 million of the $1.9 million Trump's campaign committee had received had come in the form of loans from Trump himself. Likewise, nearly all of Chafee's nearly $400,000 came from his own pockets.

Of course, that's just the data through the end of June. Trump seems to be changing his tune on fundraising these days, as Peter Overby recently reported, working to get supporter donations.

More money is still more money

There are other ways to read this data, of course — Ted Cruz, for example, has raised a respectable $5.6 million from smaller donors, despite his massive million-dollar donation haul. Mike Huckabee, likewise, could easily be classified as a "hanger-on," given his relatively low fundraising (and poll numbers), while Clinton has her own small stable of million-plus donors.

Still, the different "shapes" of candidates' donation patterns tell you a lot about just where they're looking for support, as well as their potential future weaknesses, as we've shown.

In addition, some of these candidates are using other avenues to fundraise — some are using 527s, which can raise unlimited money, but which also can't directly support or oppose candidates, per the Center for Responsive Politics. Likewise, some are using 501(c)(4)s, nonprofits that don't have to disclose their donors...but that also face tight restrictions on their political spending.

In all of this, there's one key point to remember: more money is more money, whether it comes from a typical voter or a hedge fund manager. Clinton and Santorum may have similar-looking patterns, but she's of course in way better shape for the long haul. To finish, here's a reminder of just how uneven the dollar amounts are, after all of these relatively-even-looking distribution charts.

Copyright 2021 NPR. To see more, visit https://www.npr.org.