Making augments. I make serious cash with mk-6's
I make serious cash with MK-6's as well.
On my server, Beregen Colony, they usually go between 40k and 60k, but I usually sell mine for 42,600 each (after the GTN fee, I still get a bit more than 40k each)
I don't care if I get undercutted, cause at the end of the day, I always end up selling them all.
Armormechs can produce these the cheapest. (for me it's about 15k profit each)