Nowhere is completely safe, I raised most of my initial cash in the high-intensity combat zone at Dahan fighting for the Eranin, I rarely encountered another player there. I went through quite a few 'free sidewinders', but often wound up having a nice run with a Lakon and some fighters backing me up and waves of federal fighters coming in that were quite manageable.
You could also try a resource extraction site. In those scenarios you can just bounty hunt the 'wanted' felons and pick up cargo to sell on the black market. The only problem is the current build is a little unstable in asteroids so I find it often crashes to desktop loosing my credits. Save often. You'll still get attacked, but rarely by more than one opponent at a time.