How do you decide how much to charge for an illustration?

[maggie]

Hey guys:)
I hope I'm writing on the right subforum.


I got asked to illustrate the fashion book of a famous designer in my country (Bulgaria). 
However, I am really struggling with deciding how much I should charge. 
When I open the websites of some illustrators, drawings as the ones I need to do go like 150-200$ each. But for I book I would have to do a lot more than just one. And that would be a looooot of money.. which is fine for me but would anyone pay that much? 

People also suggested that I charge 30-60$ per hour which again seems way way way too much.
After all I live in Bulgaria and for example a salary of 2000 euro here is something extremely good and not many people get paid that much. Should I also consider that factor? Because on the other hand, work is work, no matter where you do it.


here is an example of an illustration similar to what I would have to do maybe
http://i.imgur.com/RDPGupu.jpg


Thank you very much for taking the time to read this. I would appreciate any advice!