It is unusual for teachers to buy workbooks for their students. Some schools provide the books to students as part of their fees. Other schools ask students to buy the books.
I can’t really say what teachers’ habits are re photocopying books. It’s a personal affair. I don’t recommend it though because there are copyright restrictions. If you need ideas for exercises or worksheets to use with your students, many websites provide these free of charge (including this website).
Good luck with your new career!