Where you get the mats makes no difference to the price. The mats have the same value either way. If you can't sell something for more than the mats cost why are you making it to begin with? You'd be better off selling the mats instead of decreasing your net worth selling the finished product.
This is the single biggest problem with the economy/GTN. People just cannot understand that if the mats sell for more than the crafted product, don't sell/make the crafted product.
One wrench in that though, there are random drops in the world, flashpoints, treasure hunting missions, etc that will drop an armoring, mod, purple chest, whatever. Now while we crafters have an investment of crew skill mission cost, time gathering nodes in world, etc. the player that gets the random drop has literally no expense put into that "crafted" product. Thus, that player can sell for anything (1 credit if desired) and make more of a profit than a crafter