If you’ve got kids in high school or college, you’re facing the same unpleasant expense we are: Buying textbooks.

As if tuition wasn’t already high enough, you also have to pay for books. Expensive books. That are used for only a few months. And get quickly dinged up. If we had bought them all new, our daughter’s high school books would have totaled $390. And that’s just high school!

So what can you do to save money on books?

Buy e-textbooks. Maybe. It seems cheaper up front to buy or rent ebooks your kid can read on a Kindle, iPad or other tablet. Amazon.com recently started offering ebook rentals (for up to 360 days). CourseSmart.com offers a similar option.

Challenges: All textbooks are not yet available digitally. And you don’t end up with a physical copy of a book to sell back once you’re done with it. (I personally like the idea of getting some money back for my books.) DealNews is lukewarm about ebook rentals for these same reasons. Someday, this may be the main way to get texts. But for now, there are still cheaper options.

Rent. A reasonable idea. You can rent textbooks from online retailers like Chegg, Follett, and BookRenter.com. Apparently rental prices can increase during the first few weeks of classes, so you need to get your books early.

Challenges: Making sure your kid keeps the books in extremely good condition for return. And again, you spend less up front on the books, but you get nothing back for them.

Buy new and plan to sell. Of course, you can buy at the high school or college bookstore, but you’ll pay a premium. You’ll do better buying new online. As for reselling, you can sell books back to many school bookstores, but you’ll only get about 50% of your original price. Amazon.com has a textbook buyback program, but I don’t know how picky they are about the condition of returns, and how their buyback prices compare. (Has anyone used them? Experiences to share?)

You could get a better price selling books privately. If your child is in high school, try selling as many of your kid’s core subject books all at once to a child who is a year younger. Post books to sell on your school’s website or bulletin board, if they allow it. Or sell to buyers online through places like Amazon.com or Half.com.

High School Tip: Don’t save textbooks for a sibling who is 2 or more years younger. Schools change texts frequently. The books will be outdated by the time your younger kid gets them.

The cheapest option: Buy used online and plan to sell. That’s what we did. A friend (thanks, Becky!) introduced us to GetTextbooks.com. You don’t buy directly from this site. It’s more like a search engine. You enter a textbook title or ISBN and it searches multiple online booksellers for the best deals on your books. DirectTextbook.com is supposed to be similar, but I haven’t used it myself.

When your child is done with the books, you can sell privately, either to local students or online.

By the way, Money magazine (September 2011 print edition, not yet online) agrees that this is the best money-saving option, if you don’t mind doing some online shopping and selling.

Money compared various ways of buying and selling a popular biology textbook. Buying used online and selling was the best option. The book cost $196.35 new at a college bookstore. Money found the book used online for $118. Resale cost for that book: $111.10.

Net cost to consumer: $6.90. Now that’s doable!

Final note: Involve your kid in the book-buying and -selling. If your kid is in college, that’s a given. But even high school students can take responsibility for their books.

Our plan: We bought this year’s books. However, we’ve already told our daughter that next year she’ll get a small budget for buying books–probably half of what we spent this year. She’s responsible for keeping this year’s books in top shape for resale. If she doesn’t, she’ll earn less when she sells them. Since she’s buying her next round of books, she has a lot of incentive to “sell high and buy low.” If she runs short, the additional book money comes out of her own spending money.

Guess what? She’s already erasing leftover pencil marks out of her used books.

Photo by Plutor.