其实也不全是版权的原因：
出版社抽了大部分的钱
New $50 Textbook $ %
1. Publisher 33.50 67%
2. Author 4.50 9%
3. Freight Company 1.25 2.5%
4. Revenue given to college or university for academic programs, student activities, capital improvements, systems automation, and/or reduction of school operating expenses. 4.50 9%
5. Bookstore
a. Employee salaries and benefits 5.00 10%
b. Earnings and other direct expenses including taxes, equipment, maintenance, repairs, supplies, etc. 1.25 2.5%
Total: $50.00 100%
参考资料：