Nah, straight bit-coin billing. Basically like charging a customer in S. America or Europe. Convert from USD to Bitcoin on the billing date. I can accept checks, cash, and credit cards, but all of those leave a trail. If a person is seeking actual anonymous security, they can't really get it any other way. Cash isn't even exactly anonymous -- unless it's a bit less legitimate than "grey area."
PC Repair? Most PCs are in businesses, or gamer systems, not a lot of money there -- unless you wanna' get into replacing USB ports, screens, and WiFi antennas on phones and tablets. Security Administration as consulting work is the way to go, and the way I'm going.