Unfortunately, you cannot make students/parents purchase them. I even provide exercise books (paid for myself) for about 10/15% of my students! We provide study/review materials and they "study" the notes and activities we take/do in class. We make sure the class work covers what they will need to review and revise. We cannot allow then to take the books home as we use them for multiple classes and a lot would not return them. The prevalence of the internet has made it much easier and we can provide email and web based resources as well but at least. 2-4 students in every class still don't have access at home.
To be honest, text books are not an optimal method of teaching or learning for junior (or any) student and I really only use them sparingly anyway I much prefer other methods/activities as do the students!