ComparaLibros is a free online price-comparison service that helps people in Spain find school and university textbooks at competitive prices. It is a comparator, not a bookseller: users are directed to the retailer they choose, which handles the purchase, payment, delivery and customer service. The service compares books across Casa del Libro, Fnac, Amazon, El Corte Inglés, Abacus and Imosver, showing prices with delivery costs included and updating prices daily.

Users can search by ISBN, title, author or publisher, browse books by school year, subject, publisher or school, or compare a complete school list. Lists can be entered manually or uploaded as a photo or file; the service extracts ISBNs automatically. ComparaLibros calculates the total cost of a whole list at each retailer, flags unavailable titles and can show whether splitting an order across shops would cost less after shipping. Use is free and requires no registration. ComparaLibros is funded by retailer affiliate commissions, which do not increase the customer’s price.