The Activebook, which is the ebook version of the student textbook, can be bought according to the size of your school. This means you are provided with a number of log ins to the ebook, which can be handed out to your students.
The sizes are:
extra small 1-100 students
Small (101-750 students)
Medium (751-2000 students)
Large (2001-3000 students)
extra large (3001-5000 students)