So this idea is mcoin packs you can buy from the mcoin shop or will get dropped by tough bosses. 500 mcoins will get you a pack of 400 mcoins and this can be used in trades. Why not just buy an item for them and sell the item? Let's say something costs 599 mcoin and you have maybe 540 and the other guy has maybe 250 but has gold. You can buy the pack and sell it to him and he gets his item and you get your gold. The boss drop idea is also cool because it'll give you the ultimate prize. They can be sold as "receiving" items in the arena shop to give non mcoin players more of an incentive to arena. The 500-400 is just for the example, these are not set in stone.