JUDY WOODRUFF: It's hard to overstate just how expensive college can be, more than $40,000 a year for a private school, over $34,000 for an out-of-state public school.

Many students do qualify for greater financial aid, but a start-up has come up with a way to let high school students earn money for college much earlier.

Economics correspondent Paul Solman has the story. It's part of his Making Sense series, which airs Thursdays on the "NewsHour."

PAUL SOLMAN: At the engineering classroom of a top public magnet school in Miami, Terra High School, Sebastian Rodriguez and his team's entry in a national robot competition.

SEBASTIAN RODRIGUEZ, Student: You have to pick up a lot of Wiffle balls and stack them into this canister here and then be able to propel them upwards into 6-foot-tall tubes.

PAUL SOLMAN: Turns out this whole school is as competitive as the robotniks. You need high grades and test scores just to get in.

You don't get any extra money for having built a really cool robot, do you?

SEBASTIAN RODRIGUEZ: No, not at all. Just the fun of having to build a robot.

PAUL SOLMAN: And why ask about money? Because, here, kids get paid for achievements through a college scholarship app called Raise.me.

Senior Barbara Groh:

BARBARA GROH, Student: They call them micro-scholarships, and it's all based on your portfolio, your profile.

PAUL SOLMAN: Right.

BARBARA GROH: So, for different aspects of my profile, I can get different amounts of money from different schools. So these are all my AP classes.

PAUL SOLMAN: Are these your grades?

BARBARA GROH: Yes. For getting an A, you can get $25 to $1,000, depending on the school.

PAUL SOLMAN: More than 140 colleges and universities already, from Florida state to Oberlin, Penn State to Notre Dame, using their own formulas to offer money in the form of an eventual merit scholarship for high school achievements, starting in ninth grade and guaranteed, though only if the student applies and is actually admitted.

Raise.me, a private company funded by venture capital and several foundations, charges the schools annual fees to participate. The scholarship money is provided by the schools themselves.

Take an honors or an advanced course.

BARBARA GROH: Participating in an extracurricular activity, taking the PSATs, SATs, and also for getting good scores, you can get even more money.

PAUL SOLMAN: More money for immediate achievements, says Raise.me's founder Preston Silverman.

PRESTON SILVERMAN, CEO & Co-Founder, Raise.me: Instead of waiting for four years to find out if you're going to receive any scholarship, students are getting a short feedback loop each semester, each grade they get.

ANEESH RAMAN, Raise.me: It's a huge pool of money that colleges are giving out to kids after they have applied, after they have gotten in, now goes to kids starting as early as ninth grade.

PAUL SOLMAN: Yes, it only goes to them as a promise, contingent on acceptance, says Raise.me vice president Aneesh Ramen, but no matter where they go:

ANEESH RAMAN: It motivates them to do better in high school and it prepares them better for college, so, when they go, they actually finish, get a diploma, find a job, live the American dream. That's the idea.

PAUL SOLMAN: Senior Sabrina Rosell is one of Terra's typically high achievers. But, like almost all the students here, 40 percent of whom qualify for federal school lunch aid, Rosell needs help to attend the college of her choice, nearby Florida International. It's relatively inexpensive, but, then, she has four siblings.

SABRINA ROSELL, Senior, Terra High School: It may look like my family doesn't qualify for financial aid, but it doesn't mean that I can just dish out the $6,000 for tuition every single year.

PAUL SOLMAN: The $8,000 she's earned on Raise.me thus far represents a fair chunk of that tuition.

SABRINA ROSELL: It's just like — almost like a gift in exchange for all of our hard work.

PAUL SOLMAN: Rosell's fellow students agree.

JUSTIN LEE, Senior, Terra High School: I finally found out something that I can get from working hard, besides just the good feeling from working hard, you know?

PAUL SOLMAN: But if the students at Terra don't need the motivational nudge of financial incentives, even if most need the money, students elsewhere seriously need both, says Raise.me founder Silverman.

PRESTON SILVERMAN: We spend almost all of our time reaching out to schools and school districts that are serving lower-income populations and schools that serve a large percentage of first-generation college students. Those are the students that we're most passionate about supporting.

WOMAN: How many of you want to go to college?

PAUL SOLMAN: OK, so, next morning, we joined a Raise.me reach-out rally at a distinctly non-magnet school, Carol City High.

MAN: OK. Let's take some guesses on how you much you can earn for different things on Raise. Everyone who answers right, we will give you a prize.

How much do you guys think you can get for getting an A or a B in class?

PAUL SOLMAN: Carol City is just a few miles away from Terra, but in terms of academic motivation, a world apart. So will financial incentives work here?

ELONDRA JACKSON, Sophomore, Carol City High School: Yes, I do think people will try harder if they knew, like, the benefits of getting money to go to college and be successful in life.

PAUL SOLMAN: Christina Derby, Carol City high's valedictorian, doesn't need the extra incentive. But she too thinks Raise.me will instill and reinforce good habits.

CHRISTINA DERBY, Senior, Carol City High School: I think, as the money accumulates over time, then kids will be like I shouldn't fall down and get behind in my work. I should actually work harder and do more things, because, in the end, it will pay off.'

PAUL SOLMAN: But Kristin Klopfenstein, who studies the economics of education, worries that, for many kids, Raise.me will simply fall flat.

KRISTIN KLOPFENSTEIN, University of Northern Colorado: A lot of times, kids, particularly from disadvantaged backgrounds, don't understand the path from here to there. And so just saying, oh, we will reward you if you pass this test, the kids might get all excited about the incentive, but then they have no idea about how to go about actually achieving that goal.

PAUL SOLMAN: Especially with so many other distractions.

WOMAN: Another instance of violence hitting too close to a Miami-Dade school.

PAUL SOLMAN: Just hours after we left Carol City, there was a drive-by shooting out front.

STUDENT: A bunch of kids just started running, because I heard like a shot, like pop, pop, pop. Security, everybody took — getting inside.

KRISTIN KLOPFENSTEIN: I think those kids face an entirely different situation, where, when you're in an advantaged background, from an advantaged background, your time horizon can be much longer. You can be looking forward and planning for two, four years down the road: This is the college I want to go to, this is what I want to be when I grow up.

If you talk to kids who are in neighborhoods and schools like you're talking about, what do you want to be when you grow up, sometimes the kids will scratch their heads, and, you know, I don't think that far away. I may not grow up.

PAUL SOLMAN: But Klopfenstein does have an alternative.

KRISTIN KLOPFENSTEIN: Rewards for intermediate actions that lead to positive outcomes. So, for reading books or doing positive study skills and behaviors that will lead to higher grades, I will give you $2 for every book you read. That has a tremendous impact on reading comprehension.

PAUL SOLMAN: At nearby Florida International, however, an urban public university with 55,000 students, 60 percent of them Hispanic, director of admissions Jody Glassman says Raise.me had already had a positive impact. It has raised hopes for those who might not have otherwise applied.

JODY GLASSMAN, Florida International University: There's been so much hype. Is the price of a college education worth it? Are you going to be gainfully employed when you graduate? Are you going to graduate with all of this debt? And Raise.me really helps us portray to students that college is affordable.

PAUL SOLMAN: And even to the high-achieving students at the magnet school, it turns out, Raise.me has had real value. It's ratcheted up even further the drive that already spurs them.

JUSTIN LEE: We're just always competing with each other. So if one of them said, hey, I have $80,000 to this school on Raise.me, the other one will say, well, I have $82,000, and we will just keep going at it and trying to see what we can add to it.

PAUL SOLMAN: For the "PBS NewsHour," economics correspondent Paul Solman, reporting from Miami.