Buy and sell good from space stations, use the trade report. (F4 while in space, or dock with a space station and hit F3.
If you are using the interplanetary shuttle, the starting vessel you will need a cargo ship or a vessel that can carry cargo:
http://editthis.info/universalwiki/Inte ... ry_Shuttle
A cargo vessel can be found at various places. Zion Space Station has 10 right now selling for 91.0 CR. I have seen them cheaper elsewhere. I have also seen them for more (like 100 cr)
91 cr spent on a cargo vessel is not too bad, it leaves you with 9 credit to start trading food stuff and water.
The Zion Ariya Run is rather "quick" you can pick up water at Ariya for .6 credit and sell to Zion for .8 credit that is per tonne.
If you have already spent all of your money that you got with the start of the game you can reset your space vessel/economy/character with:
!resetme
That will reset only your galaxy charcter only - none of your planetside characters will be affected.
Some planets are tied into the galaxy system through Kudos I believe there is a planet that sells kudos right now for 2000 shekels. It is easier and faster to trade though.
The next start drive would be an L24 (gives you a distance of 24 parsecs) followed by L40 (a distance of 40 Parsecs).