If it’s free, what is it worth? That’s a question worth pondering as college textbook prices continue to climb, prompting efforts to replace them with free online materials.

The U.S. Government Accountability Office says textbook prices climbed an average of 82 percent between 2002 and 2012, according to a Baltimore Sun report published in The Bulletin Friday. The College Board estimates the average student is spending $1,200 each year on textbooks. That’s an excess that requires a marketplace correction.

Some see an answer in free electronic textbooks created using “open source” materials not protected by copyright. Unfortunately, the concept doesn’t account for the time and expertise required to pull together those materials into properly focused and vetted textbooks. If it’s all free, who pays for that time and expertise?

So far, most of the experimentation has depended on grant funding and donated time from college and university educators. Faculty members who have tried to save students money by pulling together their own materials have found the effort far more difficult and time-consuming than they envisioned. It’s also a challenge to get other instructors to accept material written on a volunteer basis.

The existing model of textbook production has plenty of problems, including editions being unnecessarily updated, thus increasing their cost. Online options offer the opportunity to eliminate production costs in paper and ink and transport.

But the costs of creating the intellectual material don’t go away. In fact, it’s a whole new task to take effective advantage of the interactive opportunities electronic textbooks offer.

The old textbook approach isn’t working, but the replacement hasn’t yet been found. The marketplace will need to find a sustainable business model that doesn’t depend on free labor.