The C-clips aren't that dear @6.00/4, but since you have mechanical disc brakes, there's no need to risk braking any. Slide your cable out as if they were closed loop braze-ons. Or if you do decide to spring them open warm them first by holding a rag of hot tap water against them for 10-15 seconds to soften the plastic.

The cable tie thing is always a Plan-B option, but it's not as nice a clean look.