Most schools have a recommended supply list that is issued prior to the end of the school year or during the summer. You may want to check with your school to find out whether such a list exists.
With regards to recommended supplies - it really depends upon your instructional focus. For example - if you plan to do lots of hands-on activities - you may want students to have a portfolio folder or binder to organize their lab observations.
I would also talk to another middle school science teacher. If there's another teacher on your grade level who teaches, science, you may want to touch bases with this person to get some advice.