Prepaid Mobiles

I am planning to upgrade my current phone with T-Mobile to a Samsung A177 phone. It’s an AT&T phone but i will get it unlocked to use for T-Mobile. My question is if I would need to change my current plan with T-Mobiile to a data plan to use the Samsung A177.

I already have a t-mobile phone and plan, if i were to get one of those free phones: a) would it be free b) could i still have the same plan????

I understand you won’t have im or internet anywhere but can you still use it on wifi??? Also, is it possible to buy a data plan and still keep my prepaid card?

I used to have a contract with T-mobile, but because I can’t afford to pay for it I recently got a pre-paid plan until I can. I have a sidekick, so I got the sidekick pre-paid plan which allows you to use the internet if you choose to, so anyway, I’ve been wanting to get a blackberry curve and I was just wondering, is there anyway to use the internet services on the blackberry with a pre-paid plan?

if my family plan has 5 people on it, can just one person get unlimited internet on their phone without the rest of them getting it? If so, how much more per month would it be?

I just want to use the sidekick 3 for internet but not on a contract.

My phones a Nokia 5000. Im on Boost and Optus. I have customer service and recharger. Am I on Prepaid on Plan? I bought my phone straight away yesterday like i didnt order it.

Or How can you tell if your phone is prepaid or plan?