I've done professional training, but never in a programming language. Having helped to hire trainers before in front end engineering, CSS, Javascript, HTML 5, etc, I know that their billing rates were very similar to other professional services providers. Specifically, their rate was whatever they felt reasonable. When I traveled for on site training, I would charge $2,500 to $5,000 per day, depending on how far I was traveling, etc. Local on site training was a different story, normally billed at the same exact hourly rate as I provided other clients.