The price difference between a new textbook at the campus bookstore and a used copy on AbeBooks can be 70 percent or more for the exact same edition. The fastest way to catch that difference is to scan the ISBN barcode on the back cover and compare prices across the major used-book marketplaces in one shot.
Here is the workflow that students use to save $200–$1,000 per semester.
Step 1: Find the ISBN
Every textbook has an ISBN barcode — usually on the back cover near the bottom — and the printed ISBN number above or beside it. If the book has a dust jacket, check under it; the barcode is often printed directly on the hardcover.
The number starts with 978 or 979 for modern editions. Older books may have a 10-digit ISBN-10 instead — both work for lookup.
Step 2: Scan the ISBN at ScanApp
- Open scanapp.org/isbn in any browser on your phone, tablet, or laptop.
- Grant camera permission and hold the barcode in front of your camera.
- ScanApp decodes the ISBN instantly. The number is now in your clipboard.
If your phone won’t focus close enough, take a photo of the back cover and upload it at scanapp.org/isbn — the decoder reads images the same way.
Step 3: Compare Prices Across Major Sources
Paste the ISBN into each of these to see new, used, rental, and digital prices side by side:
- Amazon — Often the cheapest for new books and bundled with Prime shipping. Search the ISBN directly to land on the exact edition.
- AbeBooks (owned by Amazon) — Specializes in used and rare textbooks. Great for older editions.
- ThriftBooks — Used books at consistently low prices with free shipping over $15.
- BookFinder — Aggregates prices from dozens of sellers including used and international editions.
- Chegg — Rental-first pricing. Usually the cheapest option if you don’t need to keep the book.
- Amazon Textbook Rentals — Rental option with a return-by-end-of-semester guarantee.
- CampusBooks — Aggregates buy, rent, and sell-back offers.
- BookScouter — Specifically for selling books back at end of semester.
For the most popular textbooks, used copies are usually 40–70% cheaper than new. Rentals can be 70–90% cheaper if you don’t need to highlight or write in the book.
Step 4: Don’t Forget International Editions
International editions of textbooks are often identical in content but printed on cheaper paper with paperback covers and a different ISBN. They sell for half to a quarter of the US hardcover price, legally, on sites like:
- AbeBooks (filter by “International edition”)
- BookByte
- eBay (search the ISBN and look for paperback or international edition listings)
Caution: international editions sometimes have different page numbers and minor problem-set variations. Verify with your professor before relying on one for problem sets.
Step 5: Check the Library
Before paying anything, scan the ISBN and search:
- Your university library catalog — many libraries reserve a copy of every textbook for in-library checkout.
- LibGen and Open Library — legitimate scanned copies of out-of-print and public-domain editions.
- WorldCat — locates a copy at the nearest library that lends it.
For courses where you only need the book for one chapter or problem set, library reserve is free and instant.
Step 6: Sell-Back Workflow at End of Semester
The same ISBN scan workflow works in reverse at the end of the term.
- Scan the ISBN at scanapp.org/isbn.
- Check sell-back offers on BookScouter (aggregates 30+ buyback services).
- Compare against Amazon Trade-In, Chegg Buy-Back, and Decluttr.
- Sell to whichever pays most. Many offer pre-paid shipping labels.
A textbook that costs $150 new and sells back for $40 effectively cost you $110. The same workflow on the buy side and the sell side is where the real savings compound.
Real Savings Examples
Three actual textbooks commonly used in undergrad courses:
| Title | New (campus store) | Used (AbeBooks) | Rental (Chegg) | Savings |
|---|---|---|---|---|
| Calculus: Early Transcendentals (Stewart, 8th ed.) | $300 | $45 | $30 | $255–270 |
| Introduction to Algorithms (Cormen, 4th ed.) | $130 | $70 | $40 | $60–90 |
| Organic Chemistry (Clayden, 2nd ed.) | $115 | $35 | $28 | $80–87 |
Across a typical four-course semester, the difference adds up to $500–$1,000 per term.
Why ScanApp for ISBN Lookup?
- Free, no app, no signup. Open scanapp.org/isbn and scan. Done.
- Privacy-first. The ISBN decoding happens in your browser. Nothing about which books you’re looking up is sent to any server.
- Works on every device. iPhone, Android, Chromebook, MacBook, Windows laptop — anything with a camera or the ability to upload a photo.
- Reads both ISBN-13 and ISBN-10, so older books work too.
Frequently Asked Questions
How do I scan a textbook’s ISBN online?
Open scanapp.org/isbn, grant camera permission, and hold the back-cover barcode in front of your camera. The ISBN appears instantly.
What’s the cheapest place to buy textbooks?
Usually AbeBooks or ThriftBooks for used copies, and Chegg for rentals. Always compare against your library and international editions first.
Can I rent textbooks instead of buying?
Yes. Chegg, Amazon Textbook Rentals, and CampusBooks offer semester-long rentals at 70–90% off the new price for popular titles.
Is it legal to buy international textbook editions?
Yes. The 2013 US Supreme Court case Kirtsaeng v. John Wiley & Sons confirmed that reselling legally purchased international editions in the US is legal. Always verify the publisher and ISBN, though.
How do I sell back my textbooks for the most money?
Scan the ISBN at scanapp.org/isbn and compare offers on BookScouter, Amazon Trade-In, Chegg Buy-Back, and Decluttr. Sell to whoever pays the most.