SOMERSET, Pa. — Before college students can crack open their books, they have to crack open their wallets and dish out money to pay for educational materials.

But doing so may become harder for students, as new editions of textbooks are constantly being published and students are already paying a considerable amount of money for tuition, room and board and other fees.

According to Make Textbooks Affordable, a campaign by Public Interest Research Groups to curtail the costs of college textbooks, students spend an average of $900 a year on books.

"The reason that textbooks are so expensive is because the economics of textbooks don't work like a normal business. Students pay whatever the publisher charges because they have to buy the books," said Nicole Allen, an advocate for the organization.

Allen said the campaign is focused on pressuring publishers to lower prices and offer more "open textbooks."

Open textbooks are similar to printed copies, but are available for free on the Internet. Information can also be printed or downloaded, and students have the option to buy a printed copy if needed.

While open textbooks may be one solution to reducing the costs of books, many subjects or editions may not be available. But the campaign may help change that.

More than 2,000 faculty members across the U.S. have joined the campaign as supporters.

Brian Sharp, an associate professor of mathematics at Indiana (Pa.) University, signed up to see the open textbooks offered online.

"Right now they are kind of limited, but hopefully there will be more in the future," he said.

Sharp tries to help students save money on books.

For his secondary math education courses he suggests students sign up as members of the National Council of Teachers of Mathematics.

For a $30 membership fee, students can have electronic access to journals and educational materials.

He also tries to keep copies of older textbooks in his office, so students who use textbooks online through a Web access code can have a hard copy to reference.

Vladimir Savinov, an associate professor of physics and astronomy at the University of Pittsburgh, also signed his name on the campaign.

"I'm trying to help my students save money," he said.

New editions are often unnecessary in Savinov's opinion. So are books that are bundled with compact discs or workbooks.

"They started bundling books with CDs and from my point of view as a physics professor this is complete nonsense," he said.

And new editions do not always mean new information.

"There really doesn't need to be improved editions. Introduction to Physics has not changed since the 19th century," Savinov said.

"In my opinion publishers are coming up with more ways to become profitable and they don't want students to reuse textbooks. They want every generation of students to spend more and more money."