Each minigame session in-game would cost X coins initially(global price).
But when player wins more than X coins(in-game reward) the cost will rise by 5% x1.05 of X, and if player wins(in-game) less than X the cost drops by 5%.
Each player win/loss adjusts the global price of minigame(at all locations) up/down on the server.
1.Dynamically adjust minigame cost to create a specific level of difficulty, allowing skilled minigame players to recoup costs and get extra coins.
2.Stops excessive reliance on minigames for coins/items/etc (due rising cost for each win).
3.Allows to award large amount of coins in-game, since the cost is balanced by cost:i.e. no junk minigames which require hours to be useful as currency/item source.