I currently have 2 lines under the ID, with each additional line it drops the monthly fee by $5.00 for Unlimited Talk and Text + 1GB data. (Optionally you can add extra data if you want on your own plan)
So right now I am paying $50/month,
with 1 more person it drops to $45 / month for everyone, all the way down to $25/month for each line once we get 7 members in the framily
This does not tie your account to mine in any way other than for the discounted service price.
If you are interested, please use my framily ID of : D00137466Ah (Case Sensitive)
https://now.sprint.com/framily/ (Link for details)