Philip Schiller, Apple's senior vice president of Worldwide Marketing, speaks about Apple's plan to "reinvent" textbooks at an event at the Guggenheim Museum on January 19, 2012 in New York City. Apple announced iBooks 2, a new free app featuring iPad interactive textbooks. The company also announced iBook Author, an application to create digital textbooks, and iTunes U, an educational app for students and teachers. Mario Tama/Getty Images

The University of Minnesota bookstore has one of the largest textbook departments in the country, with rows of shelves piled high with titles — everything from Algebra One to Nuclear Physics.

Students can buy Shakespeare's books for less than $10, but that's only because the literary rights have long ago expired. The average price of the store's books is about $50 and some titles fetch as much as $225 — another sign of the rising price of college education.

Paying for textbooks is becoming such a burden for college students, that today the University of Minnesota is launching an online project to hunt down free textbooks to replace the pricey ink-and-paper versions. It's part of a national movement to cut the cost of textbooks.

The university has an extensive used and rental program to help make textbooks more affordable. But students like Hengyi Huang try to avoid the campus bookstore altogether.

Huang, a computer science student from China, buys his textbooks on Amazon or eBay. He said it can be tricky to find the right edition required in class.

"Textbooks keep renewing every year," Huang said. "There's only a tiny change in some of the pages. But the instructor requires us to buy the newest edition, which I don't think is necessary."

The average college student spends $1,000 or more each year on textbooks. That annoys pre-med student Amanda Benarroch, of Rochester, Minn.

"Tuition is already higher than it used to be," she said. "Textbook companies are kind of obnoxious."

Obnoxious or not, commercially printed textbooks dominate the market. There's a growing effort to change that, as dozens of so-called open-source textbooks are available online for free.

But such books have been slow to catch on, said David Ernst, director of academic and information technology for the College of Education and Human Development.

"The open textbooks are out there," Ernst said. "And they're scattered."

As a result, it's hard for teachers to find them.

"The second reason is that they don't know what is quality when they do find them," Ernst said.

Written by experts in their fields, open-source textbooks generally allow users to edit the texts or make "mash-ups" from several books.

Ernst is leading a new project at the University of Minnesota that will review open-source textbooks and collect the ones that pass muster in an online catalog. He said the project will concentrate first on the most widely taught courses, like introductory biology and math.

"You know the world doesn't need another $150 Algebra One book," he said. "Algebra One hasn't changed for centuries, probably."

University of Minnesota faculty will be paid $500 to write a review of an open-source textbook. They'll earn the same amount to adopt such a book in class.

Nicolle Allen, textbook advocate for the Student Public Interest Research Group, said Minnesota's peer-reviewed catalog could be a real boost.

"There are some sites that list reviews of open textbooks but I think this one is significant because it's actually developed by a Big Ten, well-respected university," said Allen, director of the research group's Make Textbooks Affordable Project.

The catalog is part of a national effort to create cheaper alternatives to commercially published textbooks. Some educational foundations have paid scholars to write free textbooks. Other publishers offer electronic versions for free, but charge for printed copies.

But the $4 billion commercial textbook industry still retains one big advantage: the financial power to create ancillary materials like study plans, exams, and course-management software. Surveys show that instructors prize those materials above all else, said publishing industry analyst Al Greco of Fordham University.

Another priority for professors is that books be up to date and compatible with their academic viewpoint.

"While we're told price is very important, it's always fourth," said Greco, a marketing professor. "As of today, open access textbooks have very little traction in the business."

Meanwhile another big change is on the textbook horizon, Greco said.

Apple is expected to enter the college market soon, just as it has with K-12 textbooks, where publishers create multimedia textbooks for the iPad.