I keep track of time spent on a project and multiply that by my shop rate. which is .12 cents a minute,(7.20 an hour). I add all my supplies, wood (figured by board feet) and other materials. I do mainly intarsia this way but use this "formula" as a base for everything. It sounds low and may be, but it pays for my supplies, lumber included and I don't have to many projects sitting around.
The way I look at it is I going to be working in my shop making things anyways, so if I can sell something to support my hobby/addiction all the better. I've still have people say its to much(but you always will), but most pay mt asking price and several are repeat customers. My intarsia is my biggest seller, my intarsia prices as of now range from $20. for small items(like praying hands) up to $225 for larger items(eagle). I have a couple in the works that will be more but they are still based on my same formula. time x shop rate + wood = price.