There seems to be a typing mistake. The embouchure should have diameter of 2.8-3.2 centimeters, not millimeters. Perhaps that can be done DIY from an PVC pipe with an hot air gun or a gas burner to soften and shape the end. "Participants received a standardised acrylic plastic didgeridoo that was developed by the instructor in collaboration with Creacryl GmbH (Ebmatingen, Zurich, Switzerland, and costs €80 (£43; $94)…
"Perhaps that can be done DIY from an PVC pipe with an hot air gun or a gas burner to soften and shape the end." When I used to make my own PVC didgeridoos, I would melt candle wax and then dip one end repeatedly into the wax to build up wax layers until it had the desired thickness and shape.
PVC works, but the acoustics do seem superior with actual plant material. Certainly the feel.
Update: I used beeswax for the gob hole.