Hello! Paying in Mech Arena is optional. It speeds up one's progress and provides early access to the novelties, but it doesn't guarantee winning.

Hello, when the balance of the game is broken, with items that are sold, that is called  pay 2 win, then, be careful since the game seems to be growing, but you could change that with the ambition of wanting more "money", without realizing it, you would kill the game, I say this because I currently like the game, the complaint begins when I notice that players who are regularly carried by a similar environment, break the balance with items paid with "real money". 

Sorry, I don't want to offend anyone, but there are examples of economic successes in video games without breaking the balance, a good example is League of Legends.