By far the most popular IT solution for schools and the most cost effective. Microsoft offer a range of applications for both student and teacher that allow for sharing and collaboration with the click of a mouse.
Like Google, they offer a free version of their apps when using their web portal. However, to see the real power of the software you will require the full version. Applications such as Word, Excel and PowerPoint along with online storage in OneDrive prove to be the most sought after of the MS products.
The MS Office 365 portal allows for integration with your schools Active Directory and together users, licenses and email groups can be controlled seamlessly.