Noone said anything about a ship. There are mailboxes right as you start each character which you can use to mail items if you have a character just for that.
You're not making any sense. Take it from someone who has actually used them.
You can only use datacubes once. After that, clicking on the same datacube (there are four fyi) will tell you that you have nothing more to learn from it.
This means that, per character, you can only study 4 datacubes. To turn them in, you go to Nar Shaada. To get to Nar Shaada, you need a ship. This means that you need to hit level 15-16 to gain access, unless you had someone running you through your class quests, which would still take a good 4-5 hours.
Can you mail a datacube to an alt that's not bound? Sure... but the best method to exploit them was to legacy them. For someone like me with a ton of alts I was able to get a ton of credit booms and get about 1.2 million credits. I guess they didn't want to reward people with alts and decided to also make the experience boost BoP to screw long-time players over even more.