If I was you Id start of with a handful of customers. Word word of mouth will do the rest. In very short time you will be flooded. I used to charge £30 an hour and the parts I let them have at cost. Unless I was just providing the parts then I would add a bit on. The customers can be a pain in the arse some times. You always get one that constantly on the phone, how do I do this how do I do that. They think your their personal 24hr technical support.
Theres got to be an easier way to earn money