Download a project plan for building a six dollar loom to use as a first weaving experience. The pdf file includes detailed instructions on how to construct an easily transportable loom for weaving small tapestry pieces and simple weaving structure samples. The loom can be built using parts you can find at the local hardware store. There are no fancy tools involved, a drill, sandpaper, and a small handsaw or knife. You can be weaving in about an hour.
If you are planning on using this project for a class, these parts are available in bulk through McMaster-Carr.