OAKLAND — Clipboards in hand, high school seniors Estephania Franco and Jocelyn Sanchez approached a group of UC Berkeley students sitting on a curb in Sproul Plaza.

“Hey guys, you want free tuition?” one of them asked.

“Free? Tuition?” sophomore Josh Netter asked, as if waiting for the punch line. “I just feel like it’s too good to be possible.”

It wouldn’t be, if, by June, supporters of the College for California ballot petition manage to gather the signatures of 807,615 people registered to vote in the state. And, of course, if voters approve it.

The proposed constitutional amendment, researched and written a year ago as part of a senior class project at Life Academy and Oakland Unity High School, would make state university tuition-free for full-time, in-state students who maintain a 2.7 GPA or perform 70 hours of community service each year. Californians who earn more than $250,000 a year in taxable income would subsidize this additional cost through higher income taxes. The students say they want to restore the tuition-free education policy the state Legislature embraced in 1960 when it adopted the California Master Plan for Higher Education.

The chances of the effort becoming more than a lesson in democracy, however, are slim at best.

“There has not, in the modern era, been a true grass-roots initiative that has made it to the ballot,” said Thad Kousser, a political science professor at UC San Diego. By contrast, he said, “any rich person that has access to a couple million dollars basically snaps their fingers and gets access to the ballot.”

California’s century-old ballot initiative process was created to counter the powerful interest groups thought to be controlling the state government, said John Matsusaka, president of the University of Southern California’s Initiative and Referendum Institute. In practice, he said, the great number of signatures required and the short time frame in which to gather them — about five months — make it nearly impossible for even the most well-organized of citizen groups to succeed without a trove of cash and an army of paid signature gatherers.

Qualifying a statewide ballot measure typically costs $1 to $2 per signature — and, in competitive initiatives, it can rise to $10, he said.

This year, the competition for education tax measures is stiff. Gov. Jerry Brown and his allies are raising millions of dollars to put another education tax measure before voters that would raise money for public schools and community colleges. Molly Munger, a civil rights attorney and multimillionaire who is advancing her own K-12 education initiative, has spent at least $3.4 million of her personal fortune.

Without a budget, students and teachers behind College for California started a Facebook page and a website, hoping to harness some of the growing outrage over rising tuition costs, massive student loans and the nation’s growing wealth disparities, said Suneal Kolluri and Kara Duros, the teachers who are coordinating the effort.

“Our philosophy was, ‘Yeah, we don’t have money, we don’t have influence, but we have students’ ” — nearly 2 million in public high schools statewide, Kolluri said.

For the students involved in the campaign, the project is personal.

“I talk to my sister about college every day,” Franco said. “Sometimes she gets so discouraged because she knows my parents don’t make enough money to pay for it. That’s the only thing that motivates me.”

The group contacted other high school teachers, with little success. Most student leaders on university campuses were backing the higher-profile Millionaires Tax, which has since merged with Brown’s education initiative. That combined proposition does not include funding for state universities — a point the College for California team members hopes will lead more campus leaders to support their proposal. But time is running out. Their deadline is in June.

The students say they know what they’re up against; so far, they believe they have gathered only about 1,000 signatures. Still, they say that even if this attempt falls short, they will have succeeded in making people think differently about the possibilities, and maybe take it further the next time.

At UC Berkeley, some of the college students contemplated the proposal after Franco and Sanchez had moved on to a different group.

“If it was free, it’s just a crazy thing to wrap my mind around,” said Eric Tymstra, a sophomore. Netter, who sat next to him, said he wished the students luck.

“Who wouldn’t sign that petition?” he said.

Read Katy Murphy’s Oakland schools blog at www.ibabuzz.com/education. Follow her at Twitter.com/katymurphy.