when you open up the phone, there will be instructions on how to activate it (usually it takes about 5 minutes to just call in and have it activated, and you can add your minute card onto your account at the same time too) and NO they won’t charge you any "activation fee" or anything–i know this because my brother has an at&t go phone, and when he activated it, he never had to pay any fees. all you have to pay for after you initially purchase the phone is to just refill your minutes with the cards as you need it.