You'll find there are a TON of money sinks in the game in a few levels. I just bought my skills at level 22 and spent about 7000 credits. If you buy a full set of ship upgrades when you get the ship that's about 5000. If I went back and bought all the crafting recipes available to me, that would probably be another 10k. I'm also behind on leveling my investigation crew skill because of the mission cost. And I still need 20k to afford the speeder skill at 25.
Fortunately it isn't that hard to earn money... just yesterday, maybe the day before, I was down to about 1000 credits. But unless you specifically stop levelling to grind for money you won't be able to afford everything.