How much does it cost to add a line to a verizon data plan?

I need a smart phone with data and my mom has an iphone with data already. If I want to add my line to her plan, how much extra would that cost monthly?

The price to add a new line of service to that price plan will be $9.99 as long as the cell phone is not an advanced device (which requires a minimum data plan of $9.99) or a smartphone (which requires a data plan of $29.99).

The standard price to add a line is $9.99. However, if it is a smartphone (which most people use today and i can almost assume it will be) it will be $29.99 to $49.99 depending on the amount of data you want to use each month. For most people, the $30 a month for 3GB of data works out well. However if you have kids (especially teenagers. I should know, i'm one. And i'm online almost all the time) that amount could be an issue. With the amount of social networking, MMS, and data usage most kids use nowadays, it could run far past that amount per month. It is all a matter of the phone, personal need/want, and the amount it will be used.

$40 per smart phone with unlimited talk and text. You will share your moms data as long as she has the share everything plan.

This is the plan that is currently being offered and Verizon has been selling for almost a year.