It really depends on how elaborate you want to make it. It can take approximately a few hundred dollars or so to get all of the supplies you need to at least start it, including fish. After that, you can spend more if you want to.
$30-45K, you will need to rent office space in order to be taken seriously. I would say you should expect to spend an additional $20-30K on start up costs.
Know your software. In order to accurately diagnose and repair problems, you need to have a good arsenal of software that you know works. You also need to understand why...
There is no minimum, but starting a business, especially a technology-based one, can be very expensive. Figure out what you plan on selling, figure out registering fees, etc.
There are no hard and fast rules for this, and your safe distance and mine might be two different things. In general, though, I'd say that you shouldn't travel less...
