The changing editions make it harder for college bookstores to get used books in the hands of their customers, he said.
"It's a way for publishers to get away from us buying books back," said Danny Dell, bookstore manager at Hagerstown Community College.
He said publishing companies try to add study guides or CDs to update their books, but that doesn't always mean professors require the new edition or that students will buy them.
He said his customers will try to find a used book before they shell out at least 25 percent more money for a new one.
"Anything I get used goes pretty quickly," he said.
At the end of each semester, HCC's bookstore offers to buy back students' texts at half price.
He said since the bookstore is owned by the college, it has the ability to offer students that much money for their abandoned books.
"What else can you use to its full worth and then get half the money back on?" he said.
Vigil said books that are used on the Shepherd campus typically are bought back at half their cover price.
"What they get back is driven by supply and demand," he said.
For example, he said a student who buys a used textbook for $37.50, which would cost him $50 new, would get $25 back for the book at the end of the semester.
June Stotler, who manages the bookstore at Wilson College in Chambersburg, Pa., said books that are to be used the following semester are bought back from students at half price, but since the bookstore also goes through book company MBS, some books won't get nearly half their cover price.
"Textbooks are terribly expensive. It doesn't matter how you look at it," she said.
Vigil said last year students saved more than $300,000 by buying used books.
Stotler said for the most part, students come to the college bookstore to buy their textbooks. She has heard that some students attempt to buy books on the Internet, an endeavor that usually ends up tagging the same price, after shipping and handling, as the bookstore would.
"We encourage our students to be educated consumers, but they have to make sure they're comparing apples to apples and oranges to oranges," Vigil said.