If each faction has 50 members, and each player averages 300 points per hit, and each faction fights 40 battles, and each player participates evenly, and you get a free health refill for each battle, then the 10th place team would have needed 6,442 gold per player. The first place team would have needed 15,840 gold per player.
So, that is 4.3 vaults per player for the 10th place team. And 10.5 for the first place team. Or in dollars, (at $60/vault) it would be $257 for 10th, and $633 for first.
If you factor in more free hits and more faction members, this cost goes down.
If you do this same math for the top 10 teams, Gree only made $175,000 for China (not counting Apple's take).
Math is a funny thing.