After tuition and housing, buying textbooks is one of the biggest expenses for a college student.

But one Virginia Tech student is trying to change that.

Aaron Kroll, a junior majoring in business management and a 2006 graduate of Christiansburg High School, is launching Used Book Buddy, a textbook buying and selling business aimed at Tech students.

"The economy is affecting students, too," Kroll said. "They're worried about their student loans already, and then they have to spend a lot on books."

The basic idea is that Used Book Buddy will pay students more for their used books and then sell them at lower prices than traditional bookstores.

Kroll said he's bought and sold books through online venues such as craigslist.com on a smaller scale, and managed to make a profit, even while paying more for the books and selling them for less.

"The main reason [for Used Book Buddy], honestly, is to help students with their costs, not to make money," Kroll said.

The cost of books for a U.S. college student averages about $900 a year, or about 20 percent of an average student's expenses, according to U.S. PIRG, the federation of Public Interest Research Groups.

In Virginia, students paid between $300 and $400, on average, for books during the fall 2005 semester. The number of students who paid $500 or more on textbooks increased by almost 8 percent in fall semester 2005 compared with spring semester 2005, according the State Council of Higher Education for Virginia.

To buy or sell books, students can visit usedbookbuddy.com and choose "Buy Books" or "Sell Us Your Books." Sellers fill in their contact information and a list of the books they want to sell, with the ISBN number and condition. Buyers can browse by class subject for the books and choose accordingly.

The site is up now, but books won't be bought or sold until the formal launch Saturday, Kroll said.

Everyone is very sensitive to the price of books, and anywhere that gives students another place to buy and sell textbooks is a good thing, said Janine Hiller, professor of business law at Virginia Tech.

It's not to say bookstores aren't good places for students to buy and sell books, but Used Book Buddy is a local forum for students to connect, Hiller said.

Kroll is a researcher for Hiller and has run some of his ideas for Used Book Buddy by the professor.

"As a professor, I just love to see student entrepreneurs taking what they're learning in college and putting it to work," Hiller said. "This is just an example of students who are doing that."

Used Book Buddy also offers free delivery.

Kroll hopes to attend law school after he graduates from Tech, and the money he makes from the site will go toward it.

Any books that can't be resold to students the next semester will be donated to Books for Africa -- a nonprofit organization that collects books to send to primary, secondary, post-secondary and community libraries, he said.