I was actually reading an article on this today in one of my old 3D World mags. Some guy from the UK was asking how much he should charge for his freelance 3D and Matte Painting work. The mag got a guy from the industry to answer his question and he said that £20-£25 per hour was about right for London (For Matte work) but he also mentioned that Matte Painting is undervalued in London and the UK. He belives that it is valued more in America. I guess this may also be true of concept work but like Jelmer said it really depends on your skill and previous work. Good luck with it though mate hope this helps ya
