mobile . c o m n e w s a n d b l o gstmobilegoesholicraycray . htm Plus , when you also switch a number to TMobile , it gets even better . You ' ll get $ 200 of spending money per line you switch up to $ 2 , 400 on a prepaid MasterCard card ! Or , if you don ' t need a new flagship smartphone , you can even BYOD Bring Your Own Device . Just keep your old phone to use on TMobile with TMobile ONE , and you ' ll get your $ 200 per line in equal bill credits over 20 months . I interpret this as , if you got 2 lines free by signing up with a B 2 G 2 deal , without porting in native numbers assigned , you ' re good to go . So , let ' s say , I signed up for the TMO One $ 120 deal , that nets me 2 lines free , when I add 4 lines . They assign me 4 native numbers . LATER , I can port in a number on any or all of those 4 native numbers from a competitor , to take advantage of the $ 200 credit . Just because you set up a new account with TMobile doesn ' t mean you have canceled your old ATTVerizonSprint account . Porting A NUMBER in from those carriers , DOES ! NOW to me , the difference there is , in order to get the MasterCard version , instead of the account credit , you have to set up the new account , get new phones portin over the phone during this promotion ONLY , which means you do NOT get 2 free lines . And you can have a Simple Choice 6 GB 4 Lines $ 120 new account or a TMobile One UNL LTE 4 Lines $ 140 new account . So , a savings of $ 20 month , in order to get the $ 200 MasterCard is not the better deal ! But it is still a deal . Have you guys heard that Sprint is offering lines 3 , 4 and 5 free Until Jan 2018 , and then it will cost $ 30 a month for each those lines . LMAO