Portrait sketches

Hey everyone!!
I hope I'm putting this in the right place...

Basically I need to vent my creativity and due to no personal space etc atm i'm limited on how to do it (cant paint cause there is no where to fit my easal, cant knit cause the dog rips things to shreds)
So I've brought out my old sketch book and started doing sketches of people...but there is only so many randoms you can do =P
So the point of this thread is I was thinking of doing sketches for people, would be great to get some extra cash for it, but as I'm sort of new to recieving money for my pieces I have no idea on prices if its too much or not enough...
would anyone be interested? All i need is a photo and maybe a few days to get it right =)
here is some samples of ones i've done recently
Pictures by teirae - Photobucket
is it wrong to ask for a little bit of cash?
is anyone interested

thanks!!!!
-Manda