The underworld metals and luxury fabrics arent purchasable from vendors as far as i know, but there readily available on the GT on my server, so if u go slicing for money ud have to spend some of it on that.
On the other hand u dont need those to lvl it up either, u can lvl up on greens and then just have to worry about that if u want to craft blues while ur lvling or the rakata gear at 400