Textbooks have always been expensive. But gone are the days when you had no other option than to buy the hundred-dollar doorstops for full price at the school bookstore. Before the Internet, students had two choices: Buy the books or head to the library to borrow them.

Now, there are more options — perhaps too many — and shopping around for the best prices involves examining websites and making choices: Should you buy books used? Go online and have them shipped? (Amazon.com even buys back textbooks in exchange for Amazon credit.) Should you buy or rent?

Amazon recently launched a textbook rental service, and sites such as Bookrenter.com and Chegg.com allow customers to rent a book for a few months, then return it. Or you can forgo paper books entirely: Buy an e-reader and use eBooks, provided they’re available.

We formed a hypothetical course list from required reading lists at a few private high schools. Then we shopped around.

Our conclusion: It’s not hard to find the best price, so there’s no reason to pay full price. You can save hundreds of dollars by writing down the International Standard Book Number (ISBN) , then buying online. (Using the ISBN, instead of the title, will guarantee you get the correct edition). Check out our savings and the sites we tried.

Note: Prices of books can vary by the day or hour. These sales may have expired.

The bottom line: There’s no reason to spend full price on textbooks. There are options for finding deals, whether you rent, buy used or go digital. E-books will usually be cheaper than textbooks, but regardless of your preference, shopping around will save you big time.

Art History

The book: “Art Across Time, Vol. 1: Prehistory to the Fourteenth Century, 4th Edition,” by Laurie Adams

The comparison: Using the ISBN, we looked at Half.com and Amazon and used the comparison shopping site Book.ly to verify the best price. The paperback version’s list price is $142. That’s steep. Half was selling the book used for $87.41. Amazon was listing the new book for $110, used for $78. Book.ly included an eBay .com listing with a starting bid of $70.

Rental: Bookrenter rents the textbook for 125 days. The price for a college semester is $57.49. High school students, who take the class for the full year, might find it’s best to buy it used.

eBook: E-book not available for this book or edition.

Bottom line: Shopping around saves much as $70.

Calculus

The book: “Calculus: Graphical, Numerical, Algebraic,” by Ross L. Finney, Franklin Demana, Bert K. Waits and Daniel Kennedy

The comparison: Using the ISBN, we looked at Half and Amazon and used Book.ly to verify the best price. EFollet.com was offering the book new for $151.50. Half was selling it used for $95, shipping included. Amazon was selling it used for $102. Book.ly had a “Buy It Now” price on eBay of $80.

Rental: If you’re in college, renting this doorstop might be your cheapest solution. For $56.17, you can rent the book for a semester at Bookrenter. High school students might find it’s best to buy the book for the full year.

eBook: We couldn’t find the book in eBook format.

Bottom line: If you’re in a semester-long college calculus course, renting might be more practical. If you’re in high school, try to snag a used copy.

Literature

The book: “Macbeth,” by William Shakespeare

The comparison: Using the ISBN, we looked at Half and Amazon and used Book.ly to verify the best price. We found the requested edition for $6.50 used and $9 new at Half, including shipping. The list price of the edition is $10.

Rental: At Bookrenter, “Macbeth” was unavailable. But it’s so inexpensive, why would you rent?

eBook: “Macbeth” is 99 cents on Kindle. It’s free for the iPad.

Bottom line: You’re reading one of the most famous plays ever written. Buy a used paper version or download the eBook. No need to buy it at list price.

Physics

The book: “Fundamentals of Physics, Chapters 1-20 (Volume 1),” by David Halliday, Robert Resnick and Jearl Walker

The comparison: Using the ISBN, we looked at Half and Amazon and used Book.ly to verify the best price. The list price for the book is $156. Amazon was selling the hardcover book for $128.50 new and $62 used. Half.com was offering it for $90 new and $58 used. Book.ly showed an eBay auction for the edition starting at $43.

Rental: Bookrenter rents the book for $45 a semester.

eBook: There is no eBook listed for this textbook.

Bottom line: You can save more than $90 by going online and buying a used copy. If you want a new book, you can save more than $30 at Half. Renters will also save on this book, whether borrowing for one semester or two.

European history

The book: “A History of Western Society Since 1300,” by John P. McKay, Bennett D. Hill and John Buckler

The comparison: Using the ISBN, we looked at Half and Amazon and used Book.ly to verify the best price. A new book was selling for $130 at eFollet and other booksellers. Half was selling used copies for $19.23 apiece. Prices on Amazon ranged from $25 to $45 for a used edition. Here’s proof of the benefit of shopping around: At Amazon and Half, the new book was selling for a staggering $248.

Rental: Rent the book at Chegg.com for $30.99 a semester.

eBook: An eBook was not available for this title.

Bottom line: Buying a used copy can save you more than $100.