thanks again all for the helpCC is the only way, if you dont have one you can create Virtual CC, there are plenty of them available
Once you link a card I would advice using 2 step authentication on that account.
You have to be logged in to update and install the app but you can run more than one Google account on one phone, for example create a "family account" for use to buy apps but another for your email and so on.
but elimentals has understood my question