Will I be able to use the app without buying zix token?
You will have to have ZIX in your wallet in order to log in to the protocol.
How much Zix will they charge per login? is it free?
The login itself is free, but remember the ZIX token acts as a login and you will have to be holding ZIX in order to use ZEEX.
Sorry but I don't understand, should we only have a certain number of ZIX tokens in our wallet, or will each action on the platform spend a certain number of tokens?