This is how I have been making some credits.

First I'm sorry low lvls this only works for lvl 30 and above as you need to be able to run shipyard.
So you host lvl 1 on shipyard open every box kill most enemies not last 12 though it really helps If you have a eng as the eng room has 3 crates in. You get items and credits from boxes transmute items and BAM credits.

Srry if this didn't help plz no hate

Ollie