Standard Prices are as follows:
Sketch is 10$
Inked picture is 25$
Colored picture is 40$
Transformation / Comic Page is 80$ ((Uncolored)), 130$ ((colored))
Each additional character varies depending on what you're asking

Backgrounds are variable, if you just want some simple object for them to sit on that can be free, complex backgrounds are out of my element so pricing would depend on what you want.

Contact me through a note if you want to commission me, I take a "do picture first, get money after" approach to avoid procrastinating.