Aayush Phumbhra was a student at Iowa State University in Ames, Iowa, four years ago when he created an online textbook exchange.

He and his partners are now retooling the idea as a Web site where college students nationwide can rent textbooks.

Book leasing is not new, but it is creating a lot of buzz in the textbook industry because of skyrocketing textbook prices, said Lynette Seymour, manager of University Book Store on the ISU campus.

In the past, she said, leasing has worked best at smaller schools, where instructors tend to use the same text for longer periods.

"He may be on to something," she said of Phumbhra's plan. "But I'm not sure he has it all figured out yet."

Phumbhra met with University Book Store officials recently, seeking a partnership for his site, Chegg.com, Seymour said.

That's not going to happen. At least not right away, she said.

But, she said, ISU officials will watch with interest to see how Chegg.com does, and to see if leasing is an option the university-owned bookstore should consider.

Sarah Williamson, an ISU senior who leased all of her textbooks for the current fall semester from Phumbhra's online service placed an order with www.Chegg.com after seeing an advertisement for the service.

Although she discussed the service with others at the time, she said none were willing to try it when she placed her first order in August.

The service worked glitch-free for her, and she said others will likely sign up once they realize the savings.

"I saved 65 percent," or more than $400, on the six books she is now leasing, Williamson said.

Phumbhra said: "Textbooks is where students spend most of their money — $700, $800 a semester. We wanted to provide a cheaper alternative, and renting makes a lot of sense."

www.Chegg.com's business model calls for setting up centrally located warehouses nationwide and leasing books to students by the semester at 35 percent to 40 percent of the list prices.

The average life span of most books will be two to three leases, Phumbhra said.

The lease rates, along with the discounts the company receives for buying in bulk, should cover expenses, including shipping and warehousing, and provide a profit, he said.

Used books at the ISU bookstore sometimes go through as many as six owners before being retired, Seymour said.

So the www.Chegg.com model is, if anything, conservative on the expected life span of books.

The bookstore's turnover rates make it possible for students to buy and resell used books at a lower cost than the www.Chegg.com rental rate, she said.

Even with a purchase of a used book, there is a buyback risk, Phumbhra said.

It is common for instructors at schools like ISU to change textbooks, or upgrade to a newer version of the same textbook, thereby eliminating any resale value for the student.

What www.Chegg.com is doing is spreading that risk beyond a single university. With more schools, there is a better chance that the book can be reused somewhere, even if it is not at ISU, Phumbhra said.

The key to www.Chegg.com's success will be whether it is able to create that inter-school trade, Seymour said.

The name Chegg, Phumbhra said, is shorthand for the expression: "Which came first: the chicken or the egg?"