You don't have to pay yourself by the hour but it's a decent way of working out what the minimum should be. Time spent is an expense you need to cover like any other so you don't want to work at a loss.
Cover your matierial expenses too. With digital art this is hard to figure because you don't "use up" materials like you do with a real media painting. However you tools will eventually need updating, so the best way to cover your expenses is just to pad out your profit margin a bit, by whatever you think is reasonable. That way with each commission you can save a bit to your fund for replacing digital tools.
If he wants prints, don't forget to charge him the cost of the print and the p&p.
I'm a bit confused as to why you seem to have already done the painting without discussing a price?
So I need to figure out the average time I spend on different types of drawings and use the hourly rate to figure out a base price, and then add a little extra to cover expenses?
I've never charged for my work before, because I figured it wasn't good enough, but then I see other people that aren't much better getting paid commissions, so I thought I would start, but didn't really know how to. I did this picture for my cousin, and then he said he wanted to pay me, so I figured having somebody offer to pay was as good a time to start as any.
Well, the skill and experience will come with time, but I have to start somewhere, or I'll never get a chance to develop professionalism. Kind of a vicious cycle sometimes, but I guess all professionals were beginners at one point. Granted, a lot of professionals actually went to art school. I wonder if they cover classes on the business side of art.
So, if I decided to use an hourly rate, as an unknown artist starting out, should I consider minimum wage a fair price? I spent three hours on it, and the local minimum wage is $10 Canadian, so that would put it at around $30.
Well, the time spent on it is a more measurable indication of the difficulty. I mean, if it's a more challenging piece, it will take longer, right? It's just difficult to put a monetary value on the quality of your own work, or to compare it to other artists. Also, if you are a more experienced artist, you will be able to draw more quickly. I figure my time is at least worth that of a burger flipper, though. Maybe I should start offering fries with my art.
Well, thanks for trying. I think deciding where to start is the hardest part. As you get more experience and see how people react to your work and your prices, I think it will make it a lot easier to adjust accordingly.