I agree with the others, that for "grind" components, you have a couple markets:
1) lazy crafters, busy crafters, or people who really need more factories than they can get - these people are looking for factory runs in bulk, bagged up for their convenience, even better if you deliver. Walls and casks come immediately to mind, as these items take up inordinate amounts of factory time.
2) cheapskates (sorry!), who are always looking for a really good bargain - these folks will only buy dirt cheap components, and it may not be worth your time to cater to them.
3) folks reliant on components outside of their professions - smiths who need tailor crates, for example.
But for
quality components, those metrics shift. Established crafters will usually focus on these areas themselves, with their own materials, and that is how they keep their profit margins tenable. In other words, most of the people in category 1 shift to category 2, unless they are stuck in category 3. On the other hand, the "respec" market opens up to you - people who, say, respec munitions for the day, to make themselves a custom suit of armor, and are willing to pay a premium for primus cores to save themselves the hassle. Other quality-crafts (shipwright, chef, weaponsmith, etc) have less success with this, as exp suits are generally required for the final combine (not so with armorsmiths), but there's still a potential market there aiming at new (but not noob) crafters with the cash to buy-in to a profession.
I also do what Savacc does: put up a vendor with all my sub-components, which functions for both storage and sales. If they sell, awesome. If not, I'll use them eventually.
