Use the following trick to get certain items needed for trade (for example, Cooked Bile). Remember a place that has the item and go there. Once you get to a place with a lot of jars or eggs/small eggs (usually a treasure box area), break everything. If you get the desired item, exit then immediately return. The jars or eggs/small eggs have been restored. Break everything again. Note: This does not mean you will get the desired item every time. Keep repeating the process until you have enough of those items to trade. You will get items that are useful, such as Healing Potions, Healing Drinks, Antidotes, Resurrects, and Restoratives. This is especially useful just before Bosses. Also, since it is free you will not want waste any money.