When i stated Moding cell phones it was only my own phone that i worked on. However in the last few months i have worked on lots of different phones for my friends. And in doing so i have been asked what i charge for my services.
so here is the simple answer i do this work for free.
the reason being that all the software i use for moding is created but others and given to the moding community for free under the ideals of open source, therefor it would be against the ethics of open source for me to charge money for what i do. also i get help from moders and developers that are more knowledgeable then i am and they don't charge ether. However most developers do will take donations and i have donated from time to time.
If you feel the need to donate to me for the time it takes for me to find the mod you want and run it on your phone, know that i will not take money. however if you would like to buy me lunch while i work i will gladly take that
Hope this helps to answer your questions