It is mystery how sun drops(SD) were created, but they are the currency used in Maza. A good rule of thumb: one SD equals to 100 US dollars, so to a lot of Flesh Realmers, these guys are incredibly stable financially. SD's can also be used in Black Markets to purchase different items, depending on the merchant, or be traded for another type of currency(i.e. trade 5 SD's for $500). Mazans usually come to Black Markets to trade their SD's for whatever currency their new home in Gaia will accept if they're wanting to start a new life or it's for the sake of a mission. However, if they want to go back to Maza, they can trade their money back for SD's, but there's always a high probability of them going back home with less SD's if they're not cautious with their budgeting.