Hi there! @Flfilho thanks for posting your question. New lines are charged 40.00. If you go with a phone on the Next agreement, there is no activation fee.
Please keep in mind, these charges may vary if you go to a 3rd party to get your service.
If you’ve gone through an AT&T company store and were charged for activation on a Next plan, please visit that store so this can be corrected.
Thank you!
Charise