i don't generally do this, so i don't have a set number in my head to quote. most people who legally use my images do so through a usage agreement where i retain the copyright as the creator of that artwork. this is a lot more economically feasible for most individuals or companies. i imagine pricing for full copyright transfer would depend on the type of image and how much work i was doing for this person all at once or over time, among other factors. all i do know is that if i ever do this, it would be very expensive! it's sad to see how little value so many artists place in themselves when they give away their copyrights for a pittance.