What's the best Android app for finding affordable used books with a rewards program?

ThriftBooks is an Android application that caters to readers seeking economical ways to acquire books while earning benefits through purchases. The app provides access to a massive inventory of new and used titles, with prices often substantially lower than retail, making it suitable for building a personal library without overspending. A key feature is the ReadingRewards program, where users accumulate points with each transaction; these points can be redeemed for free books valued under $7, effectively reducing costs over time. Reviews indicate that shipping is typically quick, and customer service is reliable, with examples like replacements for lost shipments enhancing user trust. For real-world scenarios, such as a book enthusiast hunting for rare editions or a student sourcing affordable textbooks, the app's filtered search by condition, price, and genre streamlines the process. However, some limitations exist: inventory for specific in-demand books can be inconsistent, leading to occasional wait times, and the rewards threshold may require multiple purchases to be meaningful. Additionally, while the interface is functional, it lacks the polish of larger e-commerce apps, which might affect navigation for new users. Despite these minor imperfections, ThriftBooks balances affordability with a rewarding loyalty system, positioning it as a practical choice for frequent buyers.