Well, yeah - once you first open the applications, then they are installed, hence the "Click-to-Run." Microsoft Office is never free, although it can be very reasonably priced if you have a student discount.
As other people have said, you have a few choices:
If you really want to use an installed version of Microsoft Office, pay for the Office 365 subscription.
If you really want to use an installed application, but don't want to pay money, there's LibreOffice, OpenOffice, and many others noted elsewhere.
If you don't need a locally installed application, you can use Word, Excel, and PowerPoint in Office Online, free for personal use; or the online Google suite of productivity applications.