I've seen several types of commissions. The first is base price plus a revision price. For each revision, the revision price will get tacked onto the base price. The second is by pixel. For example, for a 800x600 image can either license for $48.00 or for the buyer to keep for $480. Another is by hour as was already mentioned and the last is by what is being drawn. A set price for b&w, color, a full body, a half-body, backgrounds, no backgrounds, an additional character, etc.
Personally, I like the base with revision price and in some cases the pixel price due to how it's cut and dry. You can basically draw anything without having to work out the pricing for each detail in the drawing. I pass on hourly because sometimes I either don't mark when I start and end or it's tough to monetize when you worked on something for 2 hours, 37 minutes and 25 seconds. Not only that but the buyer has to trust you to charge them correctly for the hours worked on the project.
On a side note, if you are getting a lot of work and don't have time to do all the requests - raise your price. It's a good indicator that there's more demand than supply and in such cases, it's alright to charge more. Also, if someone wants something done fast, charge extra. It's like getting something shipped to you the next day. If they want that service, they should pay for it.
There's a few other things but I think you're sticking to digital-only commissions so I'll leave it there. Hope that helps! : )
@ Seefy, Your link is not working D:
@ Sylux, Well not that theres anything bad but sometimes your own opinion about your own works may not be as accurate as adv from other people as some of the time people may be blinded by our own ego :C
@ Rio, The license thing is actually something I never thought off. I agree with you on the hour thing but I thing the work around if that if you are very confident with how many hours it will take, maybe you make a base fare of off that to begin with to provide a quote? Just something I thought off.
I find charging by pixel a bit weird...If its traditional like Seefy mention it kinda make sense as material cost and everything, but If its something for print on digital it just kinda...weird xD
Haha, well, I know about the pixel charging because one indie video game developer mentioned that is how she bases her fares to pay artists. Considering it's all digital and she may need images to be a specific size, it's probably more to her liking to get things priced by size and not by how long it takes. For example, video games tend to have stock art like character faces, small sprites for in-game items and all them good stuff. They're small but they add up considering a lot usually needs to be done.
That other idea could work, btw. In the end, it's up to you what you're comfortable working with when charging rates. Have you settled on rates yet?
Not really yet to be honest lol
Just wanted to explore other options and see how others are charging really. I'll probably think of something by summer.
Now that you put it that way, the pixel think kinda make a bit of sense. hmmm... never thought about it this way xD