How to charge for digital printing jobs?

[Antonio Bunt]

Hi, I found a good deal on a PIXMA 9500 and I plan to use it for my own photographic work but I want to earn a few bucks (in my case pesos). I just want to know how to calculate my expenses to charge a decent fee, not go bankrupt but not charging a prohibitely expensive price tag on prints. My problem is that mainly my material sources are in the States (inks are not sold and papers are not widely available in Mexico). So how do I make numbers? Thnaks a lot!