Every artist has a different personal formula for pricing originals. Since I had a background in graphic art and commissioned illustration work - I drew upon my experience there when I first started pricing my originals. I figured out costs of material, time spent vs hourly rate. Then over time as my work has become more popular and subsequently more valuable and in more demand I've been able to raise the prices. This is the "formal" formula I use. But most of the time these days I just go with my gut. As I was just telling a friend on the phone literally minutes ago - "These days I price my work based on how much money I need to receive to feel consoled once the work is out of my possession. The pieces are like children to me. It's never been easy for me to sell originals. So I price based on how much money I need to see in my bank account to not cry when a piece has left me." That's a colorful explanation I know. And in the wrong hands it could result in ridiculous pricing. So you have to have some perspective. You can't say "I need 50 million not to cry about this painting leaving me". Cuz unless your Damien Hirst you're not gonna get 50 mill.