In all seriousness, Buck, if you want to market to the masses then $15-$25. Realistically, with your expertise, $35-50 is not unreasonable. However, I have found, beginning builders who need patterns that are simple in order to learn and develop their own art are reluctant to drop big bucks into a pattern. A more knowlegeable builder will pay more just to see your ideas and to see if they can adapt your ideas into theirs. (Of course, Jim warned against studying what someone else is doing too much, it stiffles the "figure it out" factor.)
Same thing with painting. Alot of budding artist start with water colors because they are cheap and easy to use compared to, say, oil paints.
I realize this is a non-answer, but best of luck in deciding.
Of course I say: "I'd buy that for a dollar!"