I wasn't to happy with the idea of the coins being purchasable, I'm not all rage quite, i understand. Here are some other ideas that might help with generating an money each month to keep the servers running. One time purchase Different skins for Summons. Can have seasonal skin releases. Some earth elemental examples; Christmas: Coal, Summer: Sand and so on. Can also have alternate non seasonal skins that just make that players summon a bit more personal. This can be in a menu with the settings that players who purchase it can set. But anyone can see them on other players who have them active.Weapon element skins. Different color and/or animation of the elements. Can also have seasonal skins. Monthly Subscription This again would be purely cosmetic. Player can gain an option to have the title Patron. On the over map they can move around as a carriage instead of their avatar. Can have horns play when the player enters a zone. things can be added to keep players interested.
I like the summon skins idea, tho I actually think seasonal skins would make sense as an intrinsic part of the spell. However, I know this was intended for generating income, so I'll say other cosmetic skins for summoning would be a cool idea.