How much does it cost to add an iphone to your phone plan?

How much does it cost to add an iphone to your phone plan?

Added (1). My mom had unlimited everything for her android phone. How much would it cost to add an iphone to her plan and have unlimited everything?

It depends on your plan and how much data you use. All plans would require some type of data plan for any smartphone. On ATT for example, on the family value plan - if you have under 8gb of data to share and you have a 2 year contract then it's $40 per line. If you own the phone then it's $25 per line. If you already have a 10gb plan then it's only $25/line for a 2 year or $15/line if you own the phone. However another user usually requires more data so say another $20/2gb per person on top of the line charge plus $10 in taxes per month.

Call your service providers (ATT, Sprint, Verizon, or whoever you're using… Costs vary).