My brother is always complaining about his cell phone and service and it expires soon, so as a Christmas gift I want to get him a new phone and service with AT&T. Will they let me purchase a new phone and set up a service without him and then maybe he can come in and activate it after wards? How would this work? Would I still be able to buy the phone at the discounted price?

I have one laptop.No phone.Need internet service and am willing to purchase cell phone service for primary purpose of setting up internet service for laptop.
How is this done?How much dose it co$t?Whats best inexpensive plan?