well, here is the suggestion.
Almost everywhere you spend some money on it you accumulate points where can be traded for something usefull.
Why in Warspears should be different? My suggestion is that after every time you buy miracle coin, you get some loyalty points (like if you buy 8400 MCs you get 84 Loyalty points... something like this).
Then we should have some Loyalty club market where you can use the points and buyspecial costumes, skins, and other things...
well, I think that this may increase your MC's sales and give a little prestige to mcs users...