College-textbook shopping test: Amazon's prices for used books are consistently low

College students shopping for used textbooks online this semester should first check out Amazon. In Consumer Reports' first-ever college-textbook shopping test of five popular websites for college textbooks, Amazon's used-textbook prices were consistently low. Barnes & Noble generally posted higher prices for used textbooks.

Among the five online vendors tested—Amazon, Barnes & Noble, Bookbyte, Chegg, and TextbookRush—Bookbyte and Chegg are also worth considering. They sometimes had the lowest prices, though in our test Chegg also had the highest price for one title.

We found no marked difference among the websites in the pricing of new books. Our small sample included five popular textbooks.

Want to know more about College Textbooks? Read the Consumer Reports Back-to-School Shopping Guide.

Used texbooks. On average, we found that Amazon was most consistent in its low pricing, though it never had the cheapest price for any individual book. In contrast, Bookbyte and Chegg's prices were very variable. Sometimes they had the lowest prices, and sometimes their prices were very high.

With one exception, Barnes & Noble was found to be the most expensive. For example, Barnes & Noble marked "Sociology in Our Times: The Essentials," at $122.07, as compared to the cheapest price of $5.49, on Chegg.

Our test only looked at titles purchased directly from the website vendors. We did not compare prices of used books sold via the sites' marketplaces, where individuals and independent book vendors sell their wares.

Bottom line: Check out Amazon, Bookbyte or Chegg first. But make sure to view titles offered through the marketplace option offered by several of these companies; you might get lucky and find a better bargain. Prices also may change depending on the season, availability, and other factors.

New texbooks. We found no significant pattern in the pricing of new textbooks.

In a some cases, the new book titles were not available. At the time that we searched, Bookbyte had all five of the titles available on our first visit, and four on our second visit. Chegg only had two of the five on both visits. Amazon had three of the five on our first visit and four on our second. And at Barnes and Noble and TextbookRush, three of the five titles were available on both visits. Sometimes a seller that offered the cheapest price on one title offered the most expensive price on a different title.

Bottom line: For new textbooks, compare among several sellers for a particular title. Use promo codes, coupons, or member benefits, if you can find them. Sometimes a seller's Web site will give the promo code. The vendor also may offer discounts via e-mail only, so consider registering for alerts. An online search for the book's title will show a range of prices.

—Marcy Robles