Ok after working on that commission ive tried to come up with some basic figures for commissions but then are still negotiable so long as they are ball park.

For a single pic it would be
Sketch: £10 ($13)
More tidied up sketch and background: £20-30 ($26-$39) depending on complexity
For a tidied sketch, background and basic colour: £40 - £50 ($52-$65)
For fully coloured full shaded chars: £50-£60 ($65 - $78)
For fully shaded everything and lighting effects if required £60-£70 ($78 - $91)

Each additional panel would be half price the original cost so for a 2 panel sketch it would be £15 ( $19 ) and a 2 panel fully coloured, shaded and light effected etc would be £105 ( $137 )

Ive asked both commissioners and people who do commissions and theyve told me that seems fair but depending on complexity etc I'll happily negotiate a more fair price.

Im currently open to accept commissions from anyone interested, just send me a note ^^