I'm still on my mom's plan.
It's just way cheaper that way. I have an iPhone - base rate for my plan since it's an add-on line is $10, plus $25 for data plan, and like $20 for unlimited texting. We are on AT&T.
We have around 900 minutes, plus unused minutes roll-over to the next month, so we've banked a lot of extra ones. Unlimited AT&T mobile-to-mobile, unlimited nights and weekends, unlimited texting on all 4 lines. 2 lines (mine and brother) with data packages. I have no idea how much the entire monthly bill for the 4 of is.
We haven't run into any service issues, and we've basically been on the same plan 2002.