Commisions - What is a fair price? [Writing]

[RavenRift]

Since I put my email address into my fictionmania story, people have been emailing me for commissions. I am not opposed to this, in fact I am very excited to be taking on commissions. My issue, though, is that I have no idea where to start price wise. A chapter of Wet Dream (part II, since those chapters are longer) is about 3500-4000 words long and can take up to 5 hours to write. Within that chapter I get in a transformation, a sex scene, and dialogue before, between, and afterwards.

I was thinking of $10/thousand words, minimum of 4000 words. Does that seem to low? Too high?

Should porn be charged more than R-rated material?

I would also like to note that I don't edit Wet Dream, but I would edit commissions.