Leathercrafting is self-sustaining until the mid-30's without using levequests. You can gather the alumen and its takes about 1-2 hours to farm 99 skins/hides. You can grind 2-3 leves just by converting the skins then use the crafting recipes to grind up to the next hide or skin. It only costs you time and you make money by selling the products on the AH or to NPCs. Instead of paying 400k, I've made 400k by doing this with all the crafts and I still have 100 levequests to grind undesirable things like DoL leves :P.