How much will i have to pay to get a new t-mobile phone + number?

If i go in to the store and purchase a phone there, and activate it and everything in the store, Aside from the initial charge of what the phone costs, how much will i end up having to pay? Is there an activation fee for T-Mobile? Do i have to pay the first month in advance? Thank you|||It it $35 to activate a phone and no you do not pay the first months bill in advance.|||The activation fee is $35 but there may be other costs associated dependent on a credit check. And YES you MAY need to pay the first months bill in advance, again it's all about the credit check.