Progress in the story until you unlock the "Prickly Predicament" three star optinal quest. Talk to the Chief Botanist in the Botanical Research section to get the quest. Complete it by collecting 20 Cactuses, then return to him to unlock the ability to cultivate and grow Might Seeds. The Might Seeds are extremely valuable and can be sold for 140 zenny. Simply place a might seed in the cultivation slot and let it multiply while you are out doing quests. After you return from quests, grab the might seeds and sell them at the shop. To speed the farming process up, unlock the second cultivating slot to grow twice as much. To unlock the second cultivating slot, complete the "Persistent Pests" four star optional quest. Wear the Bandit Mantle for monsters to drop rare trade-in items when attacked. To get the Bandit Mantle, complete the "Redefining The Power Couple" five star quest. Trade-in items are essentially junk items that are only useful for selling. They cannot be used to craft or upgrade -- so you do not have to worry about selling useful monster parts. To activate the Bandit Mantle, string attacks until the mantle begins to glow. Once activated, the effect will last a set amount of time, causing items to drop from the monster. Whenever you are doing quests, you can earn trade-in items with it. The higher level the monster, the more valuable the trade-in items. Everyone in your team can also use the Bandit Mantle, multiplying your earnings. Go back and fight weak monsters from earlier quests using your high-level gear, and you can get 10,000+ zenny in a few minutes. If all allies are wearing Bandit Mantles, you can get more than 30,000+ zenny in a few minutes.