A:AnswerIf you are referring to the refill pin number,the answer is yes. The refill cards all have a unique number so there's no chance of receiving a number that was already used.
A:AnswerIt’s pretty much depends on the plan you get with AT&T prepaid. If your plan is unlimited and it cost 30 dollars, two cards would take care of it. It’s not like a set dollar amount gets you a certain amount of minutes.