New to the game.....

Sorry for another question post. First, love E:D. Also, love this community. So I have taken a fancy to doing deliveries. I have an ok rig going. I'm just trying to hoard money and explore one day with a better rig. My junker is doing ok so far for trade missions. I can handle 100LY distances pretty happily at my pace. My question is, where are some good systems do do trade missions for credits? I'm not in a rush to buy a huge ship, but I'd like to make some decent bank before buying an exploring rig.

Thanks for any insight!

CMDR: The Hurricun