Now the kids are back in school, homework once again hovers over their heads like a large dark cloud – scary and threatening.

Even the best students complain about homework some of the time – it’s too hard, there’s too much of it, or they just can’t figure out this or that problem – often in math or science.

Parents often can’t provide all that much help, for a variety of reasons, so if they can afford it – and that’s a big if – they may try to hire a tutor.

Tutoring is big business in the US, estimated at some $10 billion a year, but the sticker shock for families, often running to $60-100/hour, puts this option beyond the reach of most.

To disrupt this broken model, San Francisco-based startup InstaEDU has established an intriguing new model that matches college students from top universities with those (mostly high school students) for on-demand tutoring sessions that cost only $0.50 per minute.

“What we're trying to do its make one-on-one tutoring accessible to everyone,” says co-founder and CEO Alison Johnston. “The traditional tutoring companies are drastically overcharging students and their parents.”

What makes InstaEDU attractive is not just the reduced cost, but also the on-demand nature of its service.

“Cost is a big issue, but scheduling is another,” notes Johnston. “Not every student needs help at a specific hour you can predict ahead of time. There is a lot of 'Oh no! It's 10 p.m., and I need help with two math problems' out there…”

Johnston has got that one right.

The company has already signed up around 1,000 tutors from universities like MIT and Stanford, with skills skewing toward the subjects where high school students need the help most – math and science – but covering all the other main subjects as well.

“All tutors sign in with Facebook Connect,” says Johnston. “It streamlines the process, and allows us to verify their identity, their EDU email address, and that they indeed are students where they say they are.”

The tutors indicate when they are available for hire by being signed into either Facebook chat or g-chat. When a request comes in for, say, a math tutor, InstaEDU messages several potential candidates, and the first one who responds gets the job.

“Our average match time is down to 37 seconds,” says Johnston.

So, think about that: It’s 10 p.m.; your kid has stalled on two math problems, and is near tears with exhaustion and frustration.

Rather than telling them to give up and wait until next Thursday when their tutor will show up (and bill you for an hour), they can now go online, meet a qualified college student in less than a minute, and get the help they need right now.

Besides text chat, there is also video chat, and tools like file sharing, a whiteboard, collaborative worksheet, and a text editor. The tutor and student can work together pretty much as efficiently as if they were together in person.

Some ten- fifteen minutes later, at a total cost to you of $5-7.50, your kid’s homework is done, the crisis is solved, and he or she can get to sleep before the next morning’s early start of the school day.

“For high-schoolers, it's usually more fun to be taught by a college student,” says Johnston. “And though every student learns differently, the research indicates that some human contact is necessary for almost everyone.

“The tutors like helping the kids as well. It’s a source of income for them. They don't have to drive anywhere, but can do it from their dorm room. They work on their own schedule.”

If for any reason a tutor can’t solve the problem at hand, there is a “void” button, and the session can be ended at no charge to the student’s family.

Tutors can also place a session on “hold” if he or she needs a few extra minutes to look up a solution. There is no charge when the session is on hold.

InstaEDU pays the tutors $20/hour. Since launching into public beta in May, the company has recruited tutors from around 27 universities around the U.S., and although most requests for help are in this country, others have come from as far away as China – usually for help with English.

The company has modeled its service on other p2p startups, including Airbnb and Uber.

“Uber is especially interesting because of the on-demand aspect of its service,” says Johnston. Her company also has a ratings system, whereby students can rate their tutors. At present the ratings are not visible on-site, but “in the future, like with Uber, the best-rated tutors will move to the top of the lists.”

The company’s seven-person team works from its office on Sansome Street, and is funded with a $1 million seed round from Social+Capital Partnershipplus angels.

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