StembookDeals
Austen Plummer4 min read

How to find the cheapest copy of your STEM textbook (without reading 6 tabs)

A practical playbook for STEM students: the five retailers actually worth checking, the edition trick that saves 60%, and the only site that compares them all by ISBN.

The short answer: check five retailers by ISBN — not by title — and prefer the previous edition when your professor doesn't explicitly require the latest one.

Here's the full playbook.

1. Search by ISBN, not title

Textbooks go through multiple editions. Different editions have different ISBNs. If you search by title, you'll get results from every edition mixed together, and listings often mislabel which edition they're actually selling.

Every book has a 13-digit ISBN on the back cover, above the barcode. Use that exact number everywhere. On StembookDeals, you can paste it directly into the search bar and we'll take you to the right product page.

2. The five retailers actually worth checking

Most students default to Amazon and stop there. That's leaving 30-80% on the table. Here's the honest spread:

  • Amazon — reliable, fast, but often not the cheapest on used academic books.
  • AbeBooks — Amazon-owned but a completely different marketplace. Independent booksellers list here, which means a much wider price floor for used and international editions.
  • eBay — underrated for textbooks. Peer-to-peer sellers dump copies cheap, especially in December/January and May/June when semesters end.
  • Alibris — similar model to AbeBooks, often has the cheapest used copy.
  • Pearson InformIT — direct from the publisher of many CS, math, and physics textbooks (Pearson / Addison-Wesley / Cisco Press). Best for the newest editions and occasional deep sales.

Different retailers win for different books. Griffiths E&M might be cheapest on eBay; CLRS might be cheapest on Alibris. There's no universal winner — which is the whole reason a comparison site exists.

3. The "previous edition" trick

For most STEM textbooks, the difference between the N-th and (N-1)-th edition is:

  • Minor rewording
  • A few new homework problems
  • Updated cover art

The core content — the theorems, the proofs, the physics — almost never changes meaningfully. CLRS 3rd vs. CLRS 4th? Identical for 95% of the coursework. University Physics 13th vs. 14th? Same.

And the previous edition is routinely 50-70% cheaper because nobody wants it anymore.

The catch: if your professor assigns specific homework from the current edition by problem number, the problem numbers may have shifted. Worth checking with the professor or a classmate before committing to an older edition. For lecture-driven courses or conceptual reading, older editions are virtually always fine.

4. International editions

Same content, different cover, usually printed on cheaper paper, sold at ~70% off the US price because they're intended for developing markets. Perfectly legal to buy and use in the US — just sometimes printed in black-and-white.

Amazon and AbeBooks both carry international editions; look for listings that say "International Edition" or have an ISBN starting with something other than 978-0 or 978-1. The ISBN will be different from the US edition — another reason to search by the specific ISBN you need, not title.

5. When new actually matters

Buy new, current edition when:

  • Your professor requires you to submit specific homework problems from the book
  • The book comes with an access code for online content (Pearson MyLab, Cengage WebAssign — these are single-use codes locked to the original buyer)
  • You're buying a book you'll reference long after the course ends (Rudin, CLRS, Griffiths — bought these once, use them forever)

Otherwise, used is essentially identical value at a fraction of the price.

6. The rental trap

Textbook rental services look cheaper on paper. Run the math carefully:

  • Rent for $50, return after semester → net cost $50
  • Buy used for $60, resell at end of semester for $35 → net cost $25

Rental only beats buy-and-resell if the book has no resale value (niche intro textbooks that get a new edition every year). For canonical STEM texts — anything you'd actually want on your shelf — buying used and reselling virtually always wins.

Try it yourself

Find your textbook on StembookDeals by title or ISBN, and click through to the five retailers we compare. The spread between the cheapest and most expensive will tell you everything.

No account required, no spam, and we're transparent about how we earn on the affiliate links.

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