On the Handbook Assignment Dialog, there is a checkbox in the upper right that reads "Create a Fee record for each book assigned". If the checkmark is cleared, no fee will be created. The same is true for the Uniform Assignment Dialog.
To change the default value of these checkboxes (to avoid clearing them every time), go to Admin > Options > Misc. Clear the checkboxes under Handbook Assignment Dialog, and Uniform Assignment Dialog. (Note: In the Windows app, the Options tab is under Admin > System Settings.)