Ask this in the forum and then I'll answer with something like...
simply decide on what you think a decent hourly rate is and then charge that multiplied by no of hours taken.
I am a graphic designer and I do some video editing.
Recently a particular client wanted to compile her skating clips for her portfolio together.
I've spent about 15hrs on it (roughly) and I've had to motion track almost all of the clips because it was with an amateur video recorder (very shaky).
I've had to learn adobe after effects with this and I'd like to know very roughly the price I should be looking at to charge.