On Saturday afternoon I saw Hall Davidson give the closing keynote for the Fort Worth ISD Technology Conference. In his presentation he spoke extensively about the possibilities for use of virtual reality, augmented reality, and artificial intelligence in the classroom. One of the things that he mentioned was that you don't need to spend a lot of money in order to use virtual reality in your classroom. In fact, most schools already have the materials necessary to create virtual reality viewers. With some cardboard, glue, and plastic bottles you could build enough virtual reality viewers for a classroom.
The Google Cardboard website has templates that you can print and follow to build your own virtual reality viewers (scroll past the items listed for sale). Instructables also offers a template and directions for making your own VR viewers. And for those who would like to see the process before embarking on the project, the following video covers the process from start to finish.