artwork pricing (i need some help) art lovers opinions needed!! urgent

[nickvasko]

i need help in pricing my artwork, i do vector art and some people are now interested in me doing some artwork for them. how much is a fair rate in uk pounds? i know there are a few things i have to consider such as the print size and the complexity of the work and a few other things but i just want a guideline that i can work with, im kind of clueless. if anyone does art or sells their artwork i would be grateful for your help and even if you dont, how much would call a reasonable price?

here is a link to some of my work: http://nickvasko.deviantart.com/gallery/

thanks in advance