the only steady income from a gathering job that never changes and always sells is Crystals of varying levels. every crafter will always need shards / crystals / clusters. however you cant just check the MB once a day since as the poster above said there will always be someone to undercut you. Selling them in smaller groups will net you some leeway on pricing tho since people are willing to pay a slight markup in order to not have to buy 500 when they only need 50